i tried that too aswell b4, but only you can do is copy the shape. The only way is using the traits , and farming playing with different species and sizes (Tiny, Small, Normal, Medium, Large, Huge, & Gigantic) and you can combo with Traits too for turn them more or less big or short.
So example if combines M with L you can get a M but also a L, G + M you can get M, L, H and G specially if you added trait for increase size, the same if you wanna make them more small T + S + decrease size treat can burn to S, T+G+Decrease trait can get S, T, M, L , H and G, but will get more chances with the trait to obtain a S or a T.
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