math.points: Utility words for two and three dimensional points

extra/math/points/points.factor

@@ -0,0 +1,22 @@
+
+USING: kernel arrays math.vectors ;
+
+IN: math.points
+
+<PRIVATE
+
+: X ( x -- point )      0   0 3array ;
+: Y ( y -- point ) 0 swap   0 3array ;
+: Z ( z -- point ) 0    0 rot 3array ;
+
+PRIVATE>
+
+: v+x ( seq x -- seq ) X v+ ;
+: v-x ( seq x -- seq ) X v- ;
+
+: v+y ( seq y -- seq ) Y v+ ;
+: v-y ( seq y -- seq ) Y v- ;
+
+: v+z ( seq z -- seq ) Z v+ ;
+: v-z ( seq z -- seq ) Z v- ;
+