A computer device having a user interface configured to display user actuatable game elements in a game board and to detect user input when a user engages with a game element in a move; a processor configured to receive a detected user input and on detecting a match game condition to control the user interface to remove at least three game elements from the display and to generate replacement user game elements for a subsequent move; and a graphics rendering component operable to render the game elements on the user interface, each game element having a graphical representation on a tile having a background appearance, wherein the processor is configured to determine on detecting the match game condition if at least one tile in the match game condition has an attained background appearance and if so to apply the attained background appearance to each tile of the match condition.