ply
format ascii 1.0
element vertex 4
property float x
property float y
property float z
element face 1
property list uchar int vertex_index
end_header

0.0 0.0 0.0
1.0 0.0 0.0
1.0 1.0 0.0
0.0 1.0 0.0

4 0 1 2 3