nl_tokens: gets upper - left of a 4x4 matrix into a 3x3 of vectors
pl_tokens: function mat3from4 ( out , mat4x4 ) { out [ 0 ] [ 0 ] = mat4x4 [ 0 ] out [ 0 ] [ 1 ] = mat4x4 [ 1 ] out [ 0 ] [ 2 ] = mat4x4 [ 2 ] out [ 1 ] [ 0 ] = mat4x4 [ 4 ] out [ 1 ] [ 1 ] = mat4x4 [ 5 ] <mask> [ 1 ] [ 2 ] = mat4x4 [ 6 ] out [ 2 ] [ 0 ] = mat4x4 [ 8 ] out [ 2 ] [ 1 ] = mat4x4 [ 9 ] out [ 2 ] [ 2 ] = mat4x4 [ 10 ] }