Implement modules changing shell payloads

src/RandomHelp.hs

@@ -73,6 +73,11 @@ randProb p = do
 randInCirc :: RandomGen g => Float -> State g Point2
 randInCirc = flip randInArc (2 * pi)
 
+randOnCirc :: RandomGen g => Float -> State g Point2
+randOnCirc r = do
+    a <- state $ randomR (0, 2*pi)
+    return $ r *.* unitVectorAtAngle a
+
 randInArc :: RandomGen g => Float -> Float -> State g Point2
 randInArc = randInArcStrip 0