I love the visual aspect. They areでこぼこ and おうとつ and mean bumpiness.

If I understand this 使い分け explanation, the core meaning (bumpiness) is the same. However でこぼこ is spoken and can be used in more ways: to mean miscellaneous, as an adverb, or as an adjective. おうとつ is written, and strictly a noun about bumpiness.

Anyway, I still like these characters because they’re awesome!