[seqfan] Motzkin 3D mountains

[Richard J. Mathar]

If a Motzkin Path defines a walk with U, D, H-steps from level 0
to level 0, never descending to negative levels, a rugged landscape
for that sort of crossing paths in 3D might also be defined.
Some brainstorming on that concept is in 
http://www.mpia.de/~mathar/public/mathar20200906.pdf .
Has that type of "Motzkin moutains" or "Motzkin islands" appeared
in the literature? [For the quadrangular shapes some of these arrays
may be in Hardin's OEIS sequences.]

Richard Mathar