 
     rotater.down = (frame, step) ->
         [axisx, axisy, axisz] = frame
-        phi = - Math.PI / 6 * step
+        phi = - Math.PI / 24 * step
         cos = Math.cos(phi)
         sin = Math.sin(phi)
         # by Rodrigues' rotation formula


    rotater.left = (frame, step) ->
        [axisx, axisy, axisz] = frame
        phi = Math.PI / 6 * step
        cos = Math.cos(phi)
        sin = Math.sin(phi)
        # by Rodrigues' rotation formula


    rotater.right = (frame, step) ->
        [axisx, axisy, axisz] = frame
        phi = - Math.PI / 24 * step
        cos = Math.cos(phi)
        sin = Math.sin(phi)
        # by Rodrigues' rotation formula
