What did dinosaurs ‘really’ look like? This is a breakdown of “All Yesterdays” — a book from the “All Tomorrows” author C. M. Kosemen, with John Conway and Darren Naish. Take a moment to think about the appearance of a modern bird – like a parrot, or something similar. We know these animals have relatively thick bodies, feathery coats, unique patterns, and varying colors. Now, think about a parrot’s skeleton. Based on the bones alone, these birds seem like they’d have long, slender frames — yet the layers of skin and feather coverings make them look quite different than their gaunt skeletal structures might suggest. And this exact phenomenon presents a practical challenge when it comes to reconstructing accurate depictions of dinosaurs. The challenge of capturing the forgotten peculiarities of dinosaurs is at the center of “All Yesterdays,” a book written and illustrated in part by C.M. Koseman — whose work you know from his other most famous book “All Tomorrows.”