Customblocks are a built-in terrain tileset provided in the MegaZeux editor. They are static, non-interactive solid characters alongside terrain types like Solid, Normal, and Line. Customblocks in particular allow the user to choose any artwork out of the character set to be displayed, where other solid types have a single defined appearance. This property, while making them marginally more complicated to work with, means that a MZXer with even the slightest technical or graphical inclination will use customblocks in favor of anything else almost all of the time. Customblocks are also the only solid terrain that can interact with sprites. See also: Customfloors
Customblocks can be accessed from the editor by pressing F3 and selecting them from the menu. Placing them also involves selecting a character to display, which can be changed at any time by moving over them on the board and pressing Enter.