Solutions to Exercises for November 16, 2018

The function ptriples computes all so called Pythagorean triples with components up to a certain size.

The function prefixes computes all prefixes of a given list (including the list itself) in increasing order of length.

The function suffixes computes all suffixes of a given list (including the list itself) in decreasing order of length.

The function sublists computes all sublists of a given list in increasing order of length. Here, a sublist is obtained from a list by omitting arbitrarily many of its arguments.

Variants of stack and spread that work for pictures of different dimensions (by centering smaller pictures with respect to bigger ones).

A variant of tile that works for pictures of different dimensions (by centering smaller pictures with respect to bigger ones).