v -40 -40 -40
v 40 -40 -40
v -40 40 -40
v 40 40 -40
v -40 -40 40
v 40 -40 40 
v -40 40 40 
v 40 40 40 
c 0 0 0
#starting and ending point index for the line.  the index start from 0
l 0 1
l 0 2
l 0 4
l 1 5
l 1 3
l 2 6
l 2 3
l 3 7
l 4 6
l 4 5
l 5 7
l 6 7
color 255 0 0 
#1th number indicate how may lines in the face
#line index starting from 1.  If it is negative, it means reverse the staring
# and ending point of line
f 4 7 -5 -1 2
f 4 -6 -2 3 9
f 4 12 -8 -7 6
f 4 10 11 -12 -9
f 4 1 4 -10 -3
f 4 5 8 -11 -4