A triangle
jump is a fairly common maneuver in
video games that can be used to reach high-altitude locations. This maneuver can only be executed when there are two
walls in close proximity that are facing each other. The
character leaps onto one wall, leaps off of that wall onto the other wall, leaps off of THAT wall and onto the first wall, and
repeats the process until they have either reached the top or collided with the
ceiling.
An ASCII representation quickly reveals the origin of the name.
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Culprits: Ninja Gaiden, Strider, Devil May Cry, Super Metroid, Super Mario 64, Castlevania: Circle of the Moon, Vexx, and numerous others.