Dflux: puzzle game app for iphone, ipad

Dflux seems like a 'connect the pipes' puzzle game app. Yes and no. Yes, because you must rotate the pipes in each place (no swapping).  No, because there is a mixture of colors which can be tricky.

I've played the Lite version of Dflux which offers about 10 free levels from each category of difficulty.

Give it a shot.