New Super Mario Bros.: 7-A

Oddly enough, this is a pipeworks world. The pipe takes you into an area where almost all of the platforms are pipes. Some of the pipes make small white "Wigglers" appear. They can crawl over all surfaces. There are invisible blocks to the right of the magenta platform, which allow you to go through the pipe leading to the first Star Coin. Go into the pipe cannon on the right side, then wall jump up to the pipe to reach the second Star Coin. Once you come back through that pipe, go up a pipe a white Wiggler came out of, then up the middle pipe over the teal platform. There are invisible blocks that will prevent you from going up a gap, so go to the right, then wall jump up the pipe to stand on top of it. There is a Piranha in this pipe, so be careful. Hop up the pipes going left, and go up the pipe in the corner. Go right and get a Mini Mushroom from an item block on the right, then go back left and wall jump up to reach a mini pipe next to a pipe with a Piranha Plant. This will lead to an area with coins and the third Star Coin. Leave that area and avoid Piranha Plants to reach a pipe on the right wall. Hit the stack blocks so you can go through it. This leads to the flag opens a path to the castle.