name of the game

[sophie_1003]

there was a game we used to have on our pc which is a sort of puzzle, I'll try and explain it... there was a big square made up of smaller, differently coloured squares, you used the mouse to control one of the smaller squares that was sort of an extra as it moved round the outside of the big square, you could 'push' this square into the rows that made up the big square which then pushed out the small square at the other end, I think that the aim of the game was to reduce the size of the big square by creating rows of smae coloured smaller squares. any ideas on a name?