Dear Otared,

I received list mail in condensed form, I didn’t see your mail before I sent one.

As Mikael explained, “whatever” is very nice to find the intersection point of two lines.

You can see nice examples which use “whatever” in MetaFun manual.

In my code, the next point is the intersection point of the edge and the folding line which bisect the angle of the former folding line [M,N].

H := whatever[N, N + dir(.5*angle(M-N))*u] = whatever[A,B];

Enjoy the use of “whatever”!

I made an animation of the folding process using animation module and \processMPbuffer.

But Woldgang’s code showed a way to make it using \startuseMPgraphic.

Best regards,

Dalyoung