diff --git a/extra/math/matrices/simd/simd-tests.factor b/extra/math/matrices/simd/simd-tests.factor
index 5bd61adefd..60b37f5371 100644
--- a/extra/math/matrices/simd/simd-tests.factor
+++ b/extra/math/matrices/simd/simd-tests.factor
@@ -53,6 +53,19 @@ IN: math.matrices.simd.tests
     1.0e-7 m~ 
 ] unit-test
 
+[ t ] [
+    float-4{ 0.0 1.0 0.0 1.0 } pi 1/2. * rotation-matrix4
+    S{ matrix4 f
+        float-4-array{
+            float-4{  0.0  0.0  1.0 0.0 }
+            float-4{  0.0  1.0  0.0 0.0 }
+            float-4{ -1.0  0.0  0.0 0.0 }
+            float-4{  0.0  0.0  0.0 1.0 }
+        }
+    }
+    1.0e-7 m~ 
+] unit-test
+
 [
     S{ matrix4 f
         float-4-array{
diff --git a/extra/math/matrices/simd/simd.factor b/extra/math/matrices/simd/simd.factor
index bc213fec3a..fc6c2a03f8 100644
--- a/extra/math/matrices/simd/simd.factor
+++ b/extra/math/matrices/simd/simd.factor
@@ -95,6 +95,17 @@ TYPED:: m4. ( a: matrix4 b: matrix4 -- c: matrix4 )
 
     c set-rows ;
 
+TYPED:: v.m4 ( a: float-4 b: matrix4 -- c: float-4 )
+    b rows :> b4 :> b3 :> b2 :> b1
+    
+    a first  b1 n*v
+    a second b2 n*v v+
+    a third  b3 n*v v+
+    a fourth b4 n*v v+ ;
+
+TYPED:: m4.v ( a: matrix4 b: float-4 -- c: float-4 )
+    a rows [ b v. ] 4 napply float-4-boa ;
+
 CONSTANT: identity-matrix4
     S{ matrix4 f
         float-4-array{
@@ -165,17 +176,17 @@ TYPED:: rotation-matrix4 ( axis: float-4 theta: float -- matrix: matrix4 )
 
     axis2 cc ones axis2 v- v* v+ :> diagonal
 
-    axis { 0 0 1 3 } vshuffle axis { 1 2 2 3 } vshuffle v* 1-c v*
+    axis { 1 0 0 3 } vshuffle axis { 2 2 1 3 } vshuffle v* 1-c v*
     float-4{ t t t f } vmask :> triangle-a
-    ss { 2 1 0 3 } vshuffle triangle-sign v* :> triangle-b
+    ss axis v* triangle-sign v* :> triangle-b
     triangle-a triangle-b v+ :> triangle-lo
     triangle-a triangle-b v- :> triangle-hi
 
     diagonal scale-matrix4 :> diagonal-m
 
-    triangle-hi { 3 0 1 3 } vshuffle
-    triangle-hi { 3 3 2 3 } vshuffle triangle-lo { 0 3 3 3 } vshuffle v+
-    triangle-lo { 1 2 3 3 } vshuffle
+    triangle-hi { 3 2 1 3 } vshuffle
+    triangle-hi { 3 3 0 3 } vshuffle triangle-lo { 2 3 3 3 } vshuffle v+
+    triangle-lo { 1 0 3 3 } vshuffle
     float-4 new
 
     triangle-m set-rows drop