diff --git a/extra/jamshred/deploy.factor b/extra/jamshred/deploy.factor
new file mode 100644
index 0000000000..9a18cf1f9b
--- /dev/null
+++ b/extra/jamshred/deploy.factor
@@ -0,0 +1,12 @@
+USING: tools.deploy.config ;
+V{
+    { deploy-ui? t }
+    { deploy-io 1 }
+    { deploy-reflection 1 }
+    { deploy-compiler? t }
+    { deploy-math? t }
+    { deploy-word-props? f }
+    { deploy-c-types? f }
+    { "stop-after-last-window?" t }
+    { deploy-name "Jamshred" }
+}
diff --git a/extra/jamshred/game/game.factor b/extra/jamshred/game/game.factor
index 3842816f0e..dcb82d1de0 100644
--- a/extra/jamshred/game/game.factor
+++ b/extra/jamshred/game/game.factor
@@ -1,26 +1,31 @@
 ! Copyright (C) 2007 Alex Chapman
 ! See http://factorcode.org/license.txt for BSD license.
-USING: kernel opengl arrays sequences jamshred.tunnel
-jamshred.player math.vectors ;
+USING: accessors kernel opengl arrays sequences jamshred.log jamshred.player jamshred.sound jamshred.tunnel math.vectors ;
 IN: jamshred.game
 
-TUPLE: jamshred tunnel players running ;
+TUPLE: jamshred sounds tunnel players running quit ;
 
 : <jamshred> ( -- jamshred )
-    <random-tunnel> "Player 1" <player> 2dup swap play-in-tunnel 1array f
-    jamshred boa ;
+    <sounds> <random-tunnel> "Player 1" pick <player>
+    2dup swap play-in-tunnel 1array f f jamshred boa ;
 
 : jamshred-player ( jamshred -- player )
     ! TODO: support more than one player
-    jamshred-players first ;
+    players>> first ;
 
 : jamshred-update ( jamshred -- )
-    dup jamshred-running [
+    dup running>> [
         jamshred-player update-player
     ] [ drop ] if ;
 
 : toggle-running ( jamshred -- )
-    dup jamshred-running not swap set-jamshred-running ;
+    dup running>> [
+        f >>running drop
+    ] [
+        [ jamshred-player moved ]
+        [ t >>running drop ] bi
+    ] if ;
 
 : mouse-moved ( x-radians y-radians jamshred -- )
     jamshred-player -rot turn-player ;
+
diff --git a/extra/jamshred/jamshred.factor b/extra/jamshred/jamshred.factor
index 42414b9893..3fb7113fde 100755
--- a/extra/jamshred/jamshred.factor
+++ b/extra/jamshred/jamshred.factor
@@ -1,38 +1,48 @@
 ! Copyright (C) 2007, 2008 Alex Chapman
 ! See http://factorcode.org/license.txt for BSD license.
-USING: alarms arrays calendar jamshred.game jamshred.gl kernel math
-math.constants namespaces sequences ui ui.gadgets ui.gestures ui.render
-math.vectors ;
+USING: accessors alarms arrays calendar jamshred.game jamshred.gl jamshred.player jamshred.log kernel math math.constants namespaces sequences threads ui ui.backend ui.gadgets ui.gadgets.worlds ui.gestures ui.render math.vectors ;
 IN: jamshred
 
 TUPLE: jamshred-gadget jamshred last-hand-loc alarm ;
 
 : <jamshred-gadget> ( jamshred -- gadget )
-    jamshred-gadget construct-gadget tuck set-jamshred-gadget-jamshred ;
+    jamshred-gadget construct-gadget swap >>jamshred ;
 
-: default-width ( -- x ) 1024 ;
-: default-height ( -- y ) 768 ;
+: default-width ( -- x ) 800 ;
+: default-height ( -- y ) 600 ;
 
 M: jamshred-gadget pref-dim*
     drop default-width default-height 2array ;
 
 M: jamshred-gadget draw-gadget* ( gadget -- )
-    dup jamshred-gadget-jamshred swap rect-dim first2 draw-jamshred ;
+    [ jamshred>> ] [ rect-dim first2 draw-jamshred ] bi ;
 
-: tick ( gadget -- )
-    dup jamshred-gadget-jamshred jamshred-update relayout-1 ;
+: jamshred-loop ( gadget -- )
+    dup jamshred>> quit>> [
+        drop
+    ] [
+        dup [ jamshred>> jamshred-update ]
+        [ relayout-1 ] bi
+        yield jamshred-loop
+    ] if ;
+
+: fullscreen ( gadget -- )
+    find-world t swap set-fullscreen* ;
+
+: no-fullscreen ( gadget -- )
+    find-world f swap set-fullscreen* ;
+
+: toggle-fullscreen ( world -- )
+    [ fullscreen? not ] keep set-fullscreen* ;
 
 M: jamshred-gadget graft* ( gadget -- )
-    [
-        [ tick ] curry 10 milliseconds from-now 10 milliseconds add-alarm
-    ] keep set-jamshred-gadget-alarm ;
+    [ jamshred-loop ] in-thread drop ;
 
 M: jamshred-gadget ungraft* ( gadget -- )
-    [ jamshred-gadget-alarm cancel-alarm f ] keep
-    set-jamshred-gadget-alarm ;
+    jamshred>> t swap (>>quit) ;
 
 : jamshred-restart ( jamshred-gadget -- )
-    <jamshred> swap set-jamshred-gadget-jamshred ;
+    <jamshred> >>jamshred drop ;
 
 : pix>radians ( n m -- theta )
     2 / / pi 2 * * ;
@@ -46,22 +56,31 @@ M: jamshred-gadget ungraft* ( gadget -- )
     rect-dim second pix>radians ;
 
 : (handle-mouse-motion) ( jamshred-gadget mouse-motion -- )
-    over jamshred-gadget-jamshred >r
+    over jamshred>> >r
     [ first swap x>radians ] 2keep second swap y>radians
     r> mouse-moved ;
     
 : handle-mouse-motion ( jamshred-gadget -- )
     hand-loc get [
-        over jamshred-gadget-last-hand-loc [
+        over last-hand-loc>> [
             v- (handle-mouse-motion) 
         ] [ 2drop ] if* 
-    ] 2keep swap set-jamshred-gadget-last-hand-loc ;
+    ] 2keep >>last-hand-loc drop ;
+
+: handle-mouse-scroll ( jamshred-gadget -- )
+    jamshred>> jamshred-player scroll-direction get
+    second neg swap change-player-speed ;
+
+: quit ( gadget -- )
+    [ no-fullscreen ] [ close-window ] bi ;
 
-USE: vocabs.loader
 jamshred-gadget H{
     { T{ key-down f f "r" } [ jamshred-restart ] }
-    { T{ key-down f f " " } [ jamshred-gadget-jamshred toggle-running ] }
+    { T{ key-down f f " " } [ jamshred>> toggle-running ] }
+    { T{ key-down f f "f" } [ find-world toggle-fullscreen ] }
+    { T{ key-down f f "q" } [ quit ] }
     { T{ motion } [ handle-mouse-motion ] }
+    { T{ mouse-scroll } [ handle-mouse-scroll ] }
 } set-gestures
 
 : jamshred-window ( -- )
diff --git a/extra/jamshred/log/log.factor b/extra/jamshred/log/log.factor
new file mode 100644
index 0000000000..33498d8a2e
--- /dev/null
+++ b/extra/jamshred/log/log.factor
@@ -0,0 +1,10 @@
+USING: kernel logging ;
+IN: jamshred.log
+
+LOG: (jamshred-log) DEBUG
+
+: with-jamshred-log ( quot -- )
+    "jamshred" swap with-logging ;
+
+: jamshred-log ( message -- )
+    [ (jamshred-log) ] with-jamshred-log ; ! ugly...
diff --git a/extra/jamshred/oint/oint-tests.factor b/extra/jamshred/oint/oint-tests.factor
new file mode 100644
index 0000000000..401935fd01
--- /dev/null
+++ b/extra/jamshred/oint/oint-tests.factor
@@ -0,0 +1,8 @@
+USING: jamshred.oint tools.test ;
+IN: jamshred.oint-tests
+
+[ { 0 -1 -1 } ] [ { 0 1 -1 } { 0 -1 0 } reflect ] unit-test
+[ { 0 1 0 } ] [ { 1 1 0 } { 1 0 0 } proj-perp ] unit-test
+[ { 1 0 0 } ] [ { 1 1 0 } { 0 1 0 } proj-perp ] unit-test
+[ { 1/2 -1/2 0 } ] [ { 1 0 0 } { 1 1 0 } proj-perp ] unit-test
+[ { -1/2 1/2 0 } ] [ { 0 1 0 } { 1 1 0 } proj-perp ] unit-test
diff --git a/extra/jamshred/oint/oint.factor b/extra/jamshred/oint/oint.factor
index 11a89b314f..e2104b6f41 100644
--- a/extra/jamshred/oint/oint.factor
+++ b/extra/jamshred/oint/oint.factor
@@ -1,6 +1,6 @@
 ! Copyright (C) 2007 Alex Chapman
 ! See http://factorcode.org/license.txt for BSD license.
-USING: arrays float-arrays kernel math math.constants math.functions math.matrices math.vectors math.quaternions random sequences ;
+USING: accessors arrays float-arrays kernel locals math math.constants math.functions math.matrices math.vectors math.quaternions random sequences ;
 IN: jamshred.oint
 
 ! An oint is a point with three linearly independent unit vectors
@@ -9,47 +9,25 @@ IN: jamshred.oint
 ! segment's location and orientation are given by an oint.
 
 TUPLE: oint location forward up left ;
-
-: <oint> ( location forward up left -- oint )
-    oint boa ;
-
-! : x-rotation ( theta -- matrix )
-!     #! construct this matrix:
-!     #! { { 1           0          0 }
-!     #!   { 0  cos(theta) sin(theta) }
-!     #!   { 0 -sin(theta) cos(theta) } }
-!     dup sin neg swap cos 2dup 0 -rot 3float-array >r
-!     swap neg 0 -rot 3float-array >r
-!     { 1 0 0 } r> r> 3float-array ;
-! 
-! : y-rotation ( theta -- matrix )
-!     #! costruct this matrix:
-!     #! { { cos(theta) 0 -sin(theta) }
-!     #!   {          0 1           0 }
-!     #!   { sin(theta) 0  cos(theta) } }
-!     dup sin swap cos 2dup
-!     0 swap 3float-array >r
-!     { 0 1 0 } >r
-!     0 rot neg 3float-array r> r> 3float-array ;
-
-: apply-to-oint ( oint quot -- )
-    #! apply quot to each of forward, up, and left, storing the results
-    over oint-forward over call pick set-oint-forward
-    over oint-up over call pick set-oint-up
-    over oint-left swap call swap set-oint-left ;
+C: <oint> oint
 
 : rotation-quaternion ( theta axis -- quaternion )
     swap 2 / dup cos swap sin rot n*v first3 rect> >r rect> r> 2array ;
 
+: rotate-vector ( q qrecip v -- v )
+    v>q swap q* q* q>v ;
+
 : rotate-oint ( oint theta axis -- )
-    rotation-quaternion dup qrecip
-    [ rot v>q swap q* q* q>v ] curry curry apply-to-oint ;
+    rotation-quaternion dup qrecip pick
+    [ forward>> rotate-vector >>forward ]
+    [ up>> rotate-vector >>up ]
+    [ left>> rotate-vector >>left ] 3tri drop ;
 
 : left-pivot ( oint theta -- )
-    over oint-left rotate-oint ;
+    over left>> rotate-oint ;
 
 : up-pivot ( oint theta -- )
-    over oint-up rotate-oint ;
+    over up>> rotate-oint ;
 
 : random-float+- ( n -- m )
     #! find a random float between -n/2 and n/2
@@ -59,10 +37,10 @@ TUPLE: oint location forward up left ;
     2 / 2dup random-float+- left-pivot random-float+- up-pivot ;
 
 : go-forward ( distance oint -- )
-    tuck oint-forward n*v over oint-location v+ swap set-oint-location ;
+    [ forward>> n*v ] [ location>> v+ ] [ (>>location) ] tri ;
 
 : distance-vector ( oint oint -- vector )
-    oint-location swap oint-location v- ;
+    [ location>> ] bi@ swap v- ;
 
 : distance ( oint oint -- distance )
     distance-vector norm ;
@@ -71,6 +49,13 @@ TUPLE: oint location forward up left ;
     #! the scalar projection of v1 onto v2
     tuck v. swap norm / ;
 
+: proj-perp ( u v -- w )
+    dupd proj v- ;
+
 : perpendicular-distance ( oint oint -- distance )
-    tuck distance-vector swap 2dup oint-left scalar-projection abs
-    -rot oint-up scalar-projection abs + ;
+    tuck distance-vector swap 2dup left>> scalar-projection abs
+    -rot up>> scalar-projection abs + ;
+
+:: reflect ( v n -- v' )
+    #! bounce v on a surface with normal n
+    v v n v. n n v. / 2 * n n*v v- ;
diff --git a/extra/jamshred/player/player.factor b/extra/jamshred/player/player.factor
index 17843ef9c2..bea4ab4836 100644
--- a/extra/jamshred/player/player.factor
+++ b/extra/jamshred/player/player.factor
@@ -1,38 +1,68 @@
 ! Copyright (C) 2007 Alex Chapman
 ! See http://factorcode.org/license.txt for BSD license.
-USING: colors jamshred.oint jamshred.tunnel kernel
-math math.constants sequences ;
+USING: accessors colors jamshred.log jamshred.oint jamshred.sound jamshred.tunnel kernel math math.constants math.order math.ranges shuffle sequences system ;
 IN: jamshred.player
 
-TUPLE: player name tunnel nearest-segment ;
+TUPLE: player < oint name sounds tunnel nearest-segment last-move speed ;
 
-: <player> ( name -- player )
-    f f player boa
-    F{ 0 0 5 } F{ 0 0 -1 } F{ 0 1 0 } F{ -1 0 0 } <oint> over set-delegate ;
+! speeds are in GL units / second
+: default-speed ( -- speed ) 1.0 ;
+: max-speed ( -- speed ) 30.0 ;
+
+: <player> ( name sounds -- player )
+    [ F{ 0 0 5 } F{ 0 0 -1 } F{ 0 1 0 } F{ -1 0 0 } ] 2dip
+    f f f default-speed player boa ;
 
 : turn-player ( player x-radians y-radians -- )
     >r over r> left-pivot up-pivot ;
 
 : to-tunnel-start ( player -- )
-    dup player-tunnel first dup oint-location pick set-oint-location
-    swap set-player-nearest-segment ;
+    [ tunnel>> first dup location>> ]
+    [ tuck (>>location) (>>nearest-segment) ] bi ;
 
 : play-in-tunnel ( player segments -- )
-    over set-player-tunnel to-tunnel-start ;
+    >>tunnel to-tunnel-start ;
 
 : update-nearest-segment ( player -- )
-    dup player-tunnel over dup player-nearest-segment nearest-segment
-    swap set-player-nearest-segment ;
+    [ tunnel>> ] [ dup nearest-segment>> nearest-segment ]
+    [ (>>nearest-segment) ] tri ;
 
-: max-speed ( -- speed )
-    0.3 ;
+: moved ( player -- ) millis swap (>>last-move) ;
 
-: player-speed ( player -- speed )
-    dup player-nearest-segment fraction-from-wall sq max-speed * ;
+: speed-range ( -- range )
+    max-speed [0,b] ;
+
+: change-player-speed ( inc player -- )
+    [ + speed-range clamp-to-range ] change-speed drop ;
+
+: distance-to-move ( player -- distance )
+    [ speed>> ] [ last-move>> millis dup >r swap - 1000 / * r> ]
+    [ (>>last-move) ] tri ;
+
+DEFER: (move-player)
+
+: ?bounce ( distance-remaining player -- )
+    over 0 > [
+        [ dup nearest-segment>> bounce ] [ sounds>> bang ]
+        [ (move-player) ] tri
+    ] [
+        2drop
+    ] if ;
+
+: move-player-distance ( distance-remaining player distance -- distance-remaining player )
+    pick min tuck over go-forward [ - ] dip ;
+
+: (move-player) ( distance-remaining player -- )
+    over 0 <= [
+        2drop
+    ] [
+        dup dup nearest-segment>> distance-to-collision
+        move-player-distance ?bounce
+    ] if ;
 
 : move-player ( player -- )
-    dup player-speed over go-forward update-nearest-segment ;
+    [ distance-to-move ] [ (move-player) ] [ update-nearest-segment ] tri ;
 
 : update-player ( player -- )
-    dup move-player player-nearest-segment
+    dup move-player nearest-segment>>
     white swap set-segment-color ;
diff --git a/extra/jamshred/sound/bang.wav b/extra/jamshred/sound/bang.wav
new file mode 100644
index 0000000000..b15af141ec
Binary files /dev/null and b/extra/jamshred/sound/bang.wav differ
diff --git a/extra/jamshred/sound/sound.factor b/extra/jamshred/sound/sound.factor
new file mode 100644
index 0000000000..fd1b1127bd
--- /dev/null
+++ b/extra/jamshred/sound/sound.factor
@@ -0,0 +1,13 @@
+USING: accessors io.files kernel openal sequences ;
+IN: jamshred.sound
+
+TUPLE: sounds bang ;
+
+: assign-sound ( source wav-path -- )
+    resource-path create-buffer-from-wav AL_BUFFER swap set-source-param ;
+
+: <sounds> ( -- sounds )
+    init-openal 1 gen-sources first sounds boa
+    dup bang>> "extra/jamshred/sound/bang.wav" assign-sound ;
+
+: bang ( sounds -- ) bang>> source-play check-error ;
diff --git a/extra/jamshred/tunnel/tunnel-tests.factor b/extra/jamshred/tunnel/tunnel-tests.factor
index 8031678896..c6755318e6 100644
--- a/extra/jamshred/tunnel/tunnel-tests.factor
+++ b/extra/jamshred/tunnel/tunnel-tests.factor
@@ -3,8 +3,8 @@
 USING: jamshred.oint jamshred.tunnel kernel sequences tools.test ;
 IN: jamshred.tunnel.tests
 
-[ 0 ] [ T{ segment T{ oint f { 0 0 0 } } 0 }
-        T{ segment T{ oint f { 1 1 1 } } 1 }
+[ 0 ] [ T{ segment f { 0 0 0 } f f f 0 }
+        T{ segment f { 1 1 1 } f f f 1 }
         T{ oint f { 0 0 0.25 } }
         nearer-segment segment-number ] unit-test
 
@@ -15,3 +15,30 @@ IN: jamshred.tunnel.tests
 [ 3 ] [ <straight-tunnel> T{ oint f { 0 0 -3.25 } } 0 nearest-segment-forward segment-number ] unit-test
 
 [ F{ 0 0 0 } ] [ <straight-tunnel> T{ oint f { 0 0 -0.25 } } over first nearest-segment oint-location ] unit-test
+
+: test-segment-oint ( -- oint )
+    { 0 0 0 } { 0 0 -1 } { 0 1 0 } { -1 0 0 } <oint> ;
+
+[ { -1 0 0 } ] [ test-segment-oint { 1 0 0 } vector-to-centre ] unit-test
+[ { 1 0 0 } ] [ test-segment-oint { -1 0 0 } vector-to-centre ] unit-test
+[ { 0 -1 0 } ] [ test-segment-oint { 0 1 0 } vector-to-centre ] unit-test
+[ { 0 1 0 } ] [ test-segment-oint { 0 -1 0 } vector-to-centre ] unit-test
+[ { -1 0 0 } ] [ test-segment-oint { 1 0 -1 } vector-to-centre ] unit-test
+[ { 1 0 0 } ] [ test-segment-oint { -1 0 -1 } vector-to-centre ] unit-test
+[ { 0 -1 0 } ] [ test-segment-oint { 0 1 -1 } vector-to-centre ] unit-test
+[ { 0 1 0 } ] [ test-segment-oint { 0 -1 -1 } vector-to-centre ] unit-test
+
+: simplest-straight-ahead ( -- oint segment )
+    { 0 0 0 } { 0 0 -1 } { 0 1 0 } { -1 0 0 } <oint>
+    initial-segment ;
+
+[ { 0 0 0 } ] [ simplest-straight-ahead sideways-heading ] unit-test
+[ { 0 0 0 } ] [ simplest-straight-ahead sideways-relative-location ] unit-test
+
+: simple-collision-up ( -- oint segment )
+    { 0 0 0 } { 0 1 0 } { 0 0 1 } { -1 0 0 } <oint>
+    initial-segment ;
+
+[ { 0 1 0 } ] [ simple-collision-up sideways-heading ] unit-test
+[ { 0 0 0 } ] [ simple-collision-up sideways-relative-location ] unit-test
+[ { 0 1 0 } ] [ simple-collision-up collision-vector ] unit-test
diff --git a/extra/jamshred/tunnel/tunnel.factor b/extra/jamshred/tunnel/tunnel.factor
index c3f6b37fb8..139cdbfb53 100755
--- a/extra/jamshred/tunnel/tunnel.factor
+++ b/extra/jamshred/tunnel/tunnel.factor
@@ -1,23 +1,20 @@
 ! Copyright (C) 2007 Alex Chapman
 ! See http://factorcode.org/license.txt for BSD license.
-USING: arrays float-arrays kernel jamshred.oint math math.functions
-math.ranges math.vectors math.constants random sequences vectors ;
+USING: accessors arrays combinators float-arrays kernel jamshred.oint locals math math.functions math.constants math.matrices math.order math.ranges math.vectors math.quadratic random sequences vectors ;
 IN: jamshred.tunnel
 
 : n-segments ( -- n ) 5000 ; inline
 
-TUPLE: segment number color radius ;
-
-: <segment> ( number color radius location forward up left -- segment )
-    <oint> >r segment boa r> over set-delegate ;
+TUPLE: segment < oint number color radius ;
+C: <segment> segment
 
 : segment-vertex ( theta segment -- vertex )
-     tuck 2dup oint-up swap sin v*n
-     >r oint-left swap cos v*n r> v+
-     swap oint-location v+ ;
+     tuck 2dup up>> swap sin v*n
+     >r left>> swap cos v*n r> v+
+     swap location>> v+ ;
 
 : segment-vertex-normal ( vertex segment -- normal )
-    oint-location swap v- normalize ;
+    location>> swap v- normalize ;
 
 : segment-vertex-and-normal ( segment theta -- vertex normal )
     swap [ segment-vertex ] keep dupd segment-vertex-normal ;
@@ -27,7 +24,7 @@ TUPLE: segment number color radius ;
     dup [ / pi 2 * * ] curry map ;
 
 : segment-number++ ( segment -- )
-    dup segment-number 1+ swap set-segment-number ;
+    [ number>> 1+ ] keep (>>number) ;
 
 : random-color ( -- color )
     { 100 100 100 } [ random 100 / >float ] map { 1.0 } append ;
@@ -50,15 +47,15 @@ TUPLE: segment number color radius ;
 : default-segment-radius ( -- r ) 1 ;
 
 : initial-segment ( -- segment )
-    0 random-color default-segment-radius
-    F{ 0 0 0 } F{ 0 0 -1 } F{ 0 1 0 } F{ -1 0 0 } <segment> ;
+    F{ 0 0 0 } F{ 0 0 -1 } F{ 0 1 0 } F{ -1 0 0 }
+    0 random-color default-segment-radius <segment> ;
 
 : random-segments ( n -- segments )
     initial-segment 1vector swap (random-segments) ;
 
 : simple-segment ( n -- segment )
-    random-color default-segment-radius pick F{ 0 0 -1 } n*v
-    F{ 0 0 -1 } F{ 0 1 0 } F{ -1 0 0 } <segment> ;
+    [ F{ 0 0 -1 } n*v F{ 0 0 -1 } F{ 0 1 0 } F{ -1 0 0 } ] keep
+    random-color default-segment-radius <segment> ;
 
 : simple-segments ( n -- segments )
     [ simple-segment ] map ;
@@ -100,14 +97,54 @@ TUPLE: segment number color radius ;
     [ nearest-segment-forward ] 3keep
     nearest-segment-backward r> nearer-segment ;
 
-: distance-from-centre ( oint segment -- distance )
-    perpendicular-distance ;
+: vector-to-centre ( seg loc -- v )
+    over location>> swap v- swap forward>> proj-perp ;
 
-: distance-from-wall ( oint segment -- distance )
-    tuck distance-from-centre swap segment-radius swap - ;
+: distance-from-centre ( seg loc -- distance )
+    vector-to-centre norm ;
 
-: fraction-from-centre ( oint segment -- fraction )
-    tuck distance-from-centre swap segment-radius / ;
+: wall-normal ( seg oint -- n )
+    location>> vector-to-centre normalize ;
 
-: fraction-from-wall ( oint segment -- fraction )
+: from ( seg loc -- radius d-f-c )
+    dupd location>> distance-from-centre [ radius>> ] dip ;
+
+: distance-from-wall ( seg loc -- distance ) from - ;
+: fraction-from-centre ( seg loc -- fraction ) from / ;
+: fraction-from-wall ( seg loc -- fraction )
     fraction-from-centre 1 swap - ;
+
+:: collision-coefficient ( v w r -- c )
+    [let* | a [ v dup v. ]
+            b [ v w v. 2 * ]
+            c [ w dup v. r sq - ] |
+        c b a quadratic max ] ;
+
+: sideways-heading ( oint segment -- v )
+    [ forward>> ] bi@ proj-perp ;
+
+: sideways-relative-location ( oint segment -- loc )
+    [ [ location>> ] bi@ v- ] keep forward>> proj-perp ;
+
+: collision-vector ( oint segment -- v )
+    [ sideways-heading ] [ sideways-relative-location ] [ radius>> ] 2tri
+    swap [ collision-coefficient ] dip forward>> n*v ;
+
+: distance-to-collision ( oint segment -- distance )
+    collision-vector norm ;
+
+: bounce-forward ( segment oint -- )
+    [ wall-normal ] [ forward>> swap reflect ] [ (>>forward) ] tri ;
+
+: bounce-left ( segment oint -- )
+    #! must be done after forward
+    [ forward>> vneg ] dip [ left>> swap reflect ]
+    [ forward>> proj-perp normalize ] [ (>>left) ] tri ;
+
+: bounce-up ( segment oint -- )
+    #! must be done after forward and left!
+    nip [ forward>> ] [ left>> cross ] [ (>>up) ] tri ;
+
+: bounce ( oint segment -- )
+    swap [ bounce-forward ] [ bounce-left ] [ bounce-up ] 2tri ;
+