diff -urN rt_v9/cg.py rt_v10/cg.py
--- rt_v9/cg.py	2018-03-23 11:46:23.000000000 +0900
+++ rt_v10/cg.py	2018-03-24 12:41:14.000000000 +0900
@@ -40,6 +40,21 @@
 def d_setup(d):
 	# return lst [d]
 
+	kind = d.get('kind')
+
+	if kind == 'cube':
+		def cube_f( (l, deg) ):
+			d_ = d.copy()
+			d_['kind'] = 'square'
+			d_['l2m'] = [ ax.slide_z(1), ax.rot(l, deg) ] + d_.get( 'l2m', [] )
+			return d_setup( d_ )
+		rots = [
+			(line.x1, 0), (line.x1, 90), (line.x1, 180), (line.x1, -90),
+			(line.y1, 90), (line.y1, -90)
+		]
+		return sum( map( cube_f, rots ), [] )
+	###
+
 	if_not_set_opt( d, 'l2m', [] )
 	if_not_set_opt( d, 'm2g', [] )
 	if_not_set_opt( d, 'l2g', d.get('l2m') + d.get('m2g') )
@@ -65,7 +80,7 @@
 		'maps': maps,
 		'm2g': [ ax.zoom_all(50) ],
 	},{
-		'kind': 'ball',
+		'kind': 'cube',
 		'rtd': { 'base':0.1, 'diff': 0, 'reflect': 0.5, 'reflact': 0.5, 'density': 2 },
 		'def_col': [128,0,0],
 		'l2m': [ ax.zoom_all(20.0/50) ],
diff -urN rt_v9/wf.py rt_v10/wf.py
--- rt_v9/wf.py	2018-03-18 10:29:07.000000000 +0900
+++ rt_v10/wf.py	2018-03-24 12:35:50.000000000 +0900
@@ -6,8 +6,8 @@
 import lstx
 
 def wf_ps_idxs(d):
-	ps_to_idxs = lambda ps: map( lambda i: ( i, (i+1)%n ), range( len(ps) ) )
-	rv_ps = lambda ps: ( ps, ps_to_idxs(ps) )
+	len_to_idxs = lambda n, add=0: map( lambda i: ( i, (i+1)%n ), range(add, add+n) )
+	rv_ps = lambda ps: ( ps, len_to_idxs( len(ps) ) )
 
 	kind = d.get('kind')
 
@@ -34,17 +34,29 @@
 		(ps, idxs) = c3[1]
 		n = len(ps)
 		ps = map( lambda p: ax.rot_x(90).tr('l2g', p), ps )
-		idxs = map( lambda idx: map( lambda id: id + n, idx ), idxs )
+		idxs = len_to_idxs(n, n)
 		c3[1] = (ps, idxs)
 
 		(ps, idxs) = c3[2]
-		n *= 2
 		ps = map( lambda p: ax.rot_y(90).tr('l2g', p), ps )
-		idxs = map( lambda idx: map( lambda id: id + n, idx ), idxs )
+		idxs = len_to_idxs(n, 2*n)
 		c3[2] = (ps, idxs)
 
 		return map( lambda xs_lst: sum( xs_lst, [] ), zip(*c3) )
 
+	z_pn = lambda ps: map( lambda (x,y,z): [x,y,1], ps ) + map( lambda (x,y,z): [x,y,-1], ps )
+
+	def mk_prism(ps):
+		n = len(ps)
+		ps = z_pn(ps)
+		idxs = len_to_idxs(n) + len_to_idxs(n, n) + map( lambda i: (i,i+n), range(n) )
+		return (ps, idxs)
+
+	if kind == 'cube':
+		d = { 'kind': 'square' }
+		(ps, _) = wf_ps_idxs(d)
+		return mk_prism(ps)
+
 	return ([],[])
 
 def nv_clip(nv, pa, pb):