\ {[M]M|{|/M&x}'M}/;
\ {[M]M|M{|/x&y}/:M}/;
\ {[M]M|M(|/&)/:M}/;

[3 3] [0 0 0 1] # `M set;
[[dup dup [& [|] iterate] right |] converge] `tc def;
M tc;