for a cake with a tropical theme, how would I simulate a waterfall? I saw a picture of a cake with a blue jello-like waterfall cascading down the cake. how would I do that? Any suggestions?

for the waterfall I did on my jungle cake I used indydebi's buttercream and frosted the areas I wanted to be a part of the falls, then I used blue sparkles wilton piping gel over the top. I applied it with an angled spatula. then I dabs some more white buttercream to simulate foam at the base of the falls. I was really worried about how it would turn out, but it turned out really well and I was pleasantly surprised with how easy it was.

yep. piping gel. it works great.

For the cake I did, I put white fondant on the area that was meant to be water, and covered it with homemade piping gel coloured blue. At the bottom, I swirled a bit of silver coloured piping gel in the blue to simulate the froth.

I've used piping gel for a golf course lake before - I wasn't sure it would adhere vertically to a three tier cake - I guess I thought it might slide down! I really like the blue sparke gel idea! Thanks for your help!