control stick and directional pad are interchangeable. Very few games use the directional pad exclusively, such as Tetrisphere and Kirby 64: The Crystal Shards. This design is controversial, as by its nature it generally prevents the use of all of its features with the player's hands in any one position; the D-pad, L-shoulder, analog stick and Z-trigger cannot, generally, all be used at the same time as it typically requires the player to switch hand positions, taking the hands off of the key directional controls. Some, though, realized they can hold the controller with the outer grips and use their index fingers for the R and L triggers, middle fingers for the Z-trigger, right thumb for the right-hand buttons, and left thumb for the D-pad and (stretching) analog stick, without changing hand positions. When Sony released its Dual Analog and DualShock controllers for the competing PlayStation, it retained the original controllers' two-handled ergonomics, placing the analog sticks below and inside the primary D-pad and face buttons, allowing the player to quickly switch from the D-pad and face buttons to the analog sticks without letting go of the controller. Several third-party manufacturers would produce aftermarket Nintendo 64 controllers with similar layouts to the Dual Analog/DualShock, such as the MakoPad and Hori Mini. Nintendo would largely follow suit with the stock controller for its GameCube console, but swapped the positions of the analog stick and D-pad. Such a layout would become dominant in gamepad design, as by that time the left analog stick had become universally accepted as the primary movement control on 3D games across all consoles. The controller has four "C buttons" on the top, which were originally intended to control the camera in three-dimensional game environments. However, since the pad only contains three other face buttons, the C-buttons often became assigned to ulterior functions. An example of this is The Legend of Zelda: Ocarina of Time, where three of the C-buttons can be assigned to secondary items and the upper C-button is used to call Navi for assistance, while the Z-trigger is used to lock focus onto enemies and center the camera behind the player. One game, Robotron 64, allows one player to use two controllers to control an avatar. This way, the game plays like its predecessor, Robotron 2084. Star Wars Episode I: Racer, GoldenEye 007 and Perfect Dark also use this set up for slightly different gameplay