Within official franchise installments, each version has made improvements to accommodate advancing technology and the goal to provide a more complete game. Developers are given freedom to add new modes of play and revisit the concept from different angles. Some concepts developed on official versions have been integrated into the Tetris guidelines in order to standardize future versions and allow players to migrate between different versions with little effort.[7] The IBM PC version was the most evolved from the original version, featuring a graphical interface, colored tetrominoes, running statistics for the number of tetrominoes placed, and a guide for the controls.[8]