New Super Luigi U: Meringue Clouds-3 -- Rainbow Skywalk

The floor in this level is rainbow-colored. Take the arrow platform up and dodge the Bullet Bills. The first Star Coin will be on the left side while you're going up. At the top, a Waddlewing will appear with an Acorn. Grab the Acorn, and get the Green Coins if you like. Take the arrow platform to the right, across the gap. Under the right ledge is a hidden pipe. This leads to an area with a narrow gap in the ceiling. Use the POW Block to drop the second Star Coin into the gap onto an arrow platform, making it rise. Quickly wall jump up to get it before it disappears at the top of the screen. Go through the pipe to return to the main level. There's a Silver Ring here above the arrow platform. Stand on it to make it rise, then activate the Silver Ring, waiting as long as you can. Silver Coins will appear and Waddlewings will fly in. Let at least one live so it can stand on the platform for you. You have to reach the top quickly as the Silver Ring also turns brick blocks into coins. This is the only way to reach the third Star Coin at the top, in an alcove. Take an arrow platform to the right and dodge Bullet Bills to reach the flag.