What's the adjective for squarishness? Here's the word you're looking for.
Included below are past participle and present participle forms for the
verb square which may be used as adjectives within certain contexts.
square
Shaped like a square (the polygon).
Forming a right angle, especially (nautical) at right angles with the mast or the keel, and parallel to the horizon; said of the yards of a square-rigged vessel when they are so braced.
Of numbers formed by multiplying two equal numbers.
Used in the names of units of area formed by multiplying a unit of length by itself.