Triangle Holes is the 25th Advanced stage in Challenge Mode and World 6-5 in Story Mode of Super Monkey Ball 2.
The stage has one goal at the end of a platform containing triangular holes, the smallest of which are at the front and back of the platform, and the largest are at the middle. There are 2 single bananas at the back corners of the platform.
Simply hold up and you'll bounce into the goal. It's that easy!