Tap, Tap, Boom! - Quick Pitch

Blocks appear in the empty spaces on the screen, then increase in size and move in a straight line. They start out white, and as they grow, they turn black.  They continue to grow/move until one side touches a wall, once it touches a wall, it sticks to it, and is now considered part of the wall surface, and is now, "untap-able".  The player needs to tap these square shapes as they are growing to "stop" them. If enough blocks turn into walls that it fills the whole screen as a solid black square, the game is over.

While a block is being tapped, it will stop growing and moving, the value will also head back toward being white.  if the player stops tapping it, it will start growing and moving again, and start fading to black again.  If the block turns black, or hits a wall, it turns into a static object(and it's color snaps to black if it wasn't already.)
However, when it is tapped all the way back to full white, it will "explode".  When a block explodes, it shoots out a white box in all 4 directions that destroys the walls that it touches, which clears more screen for more blocks to appear.  The size of the pixel that explodes out of each of the 4 sides is based on the size the block has grown to.  Players may actually choose to wait til it gets bigger to tap it, so that when it explodes, it fires off larger square pixels.   Multiple blocks will start to appear, and further stages will start out with different arrangements of walls that need to be destroyed.  A player completes a level by surviving the time limit, or clearing the entire stage to it's boarders.

this tiny picture may help... it's really tiny though :D essentially showing that a white box appears, starts moving, growing in size, and getting darker.  it hits a wall in drawing 5, and then in drawing 8 the player decides to tap the cube headed for the right wall, he taps it 4 times, which gets it back to white, and that shoots out 4 white destroyer cubes, one of which cuts through the black cube that stuck in the corner, leaving only a thin sliver.  and the boxes keep appearing... etc.