Are they just the the same but more dramatic in the diffrent styles? TIA
A "topsy turvy" cake is usually a cake that looks like it has balance issues, often appearing as though it is stacked upside down. It generally has carved in sides and/or a slanted top, although sometimes people do them with normal-shaped cakes and separator wedges to make the tiers appear to be nearly toppling over.
I just looked up the definition of the term itself, and it hails from around 1528, when it meant "the top where the bottom should be".
Whimsical generally means any cake with excessively playful features, which would include a topsy turvy cake but could also be other styles. Some topsy turvy cakes are more whimsical in style than others though!