Soreness can theoretically be avoided by limiting exercise to concentric and isometric contractions. Participants hold their bodies still while contracting specific, targeted sets of muscles in isometric exercises. But this genre incorporates strategic gameplay such as tactical movement on an isometric grid. The view is isometric with tactical gameplay. Isometric projection is a type of axonometric projection. Strength training with isometric exercise was popularised by Charles Atlas from the 1930s onwards. There are also gameplay advantages to using an isometric or pseudo-isometric perspective in video games. Test chambers began as isometric drawings on whiteboard. Gameplay is carried out through an isometric viewpoint. "Rad" is a roguelike video game played from an isometric perspective. Played from an isometric perspective, the game will feature synchronous and asynchronous multiplayer. Combat is done in a 3D isometric point of view. Zee was inspired by the pixel art landscapes of earlier Japanese isometric games. It is diffeomorphic to a regular torus but not isometric. This implies that two isometric Euclidean spaces have the same dimension.