You can use different input Bits to control the amount of signal sent to the LED matrix. This will change the display depending on what preset you have selected. All presets require two inputs to fully control them.
The LED matrix receives serial data, which it translates into images.
When the LED matrix is in serial mode, you can use the codeBit and littleBits Code Kit app to put up to four matrices together to form a bigger image. To help you tile them in the right direction, the case enclosing each LED matrix has dimples and magnets. To display your image correctly, use the preset/ channel button on each LED matrix Bit to control which channel, and part of the image, that the matrix displays.