Just imagine.  In 1972 the first Pong! systems come out.  5 long years later, technology has advanced so that in 1977 Roberts releases the Rally IV.  Woodgrain was so 1976.  Advancements include two removable controllers, more game variations, and a plug instead of batteries.  I can only guess how excited the kids were when this appeared under the tree, and they shrieked aloud about how they could now play Pong comfortably two extra feet from the TV.  And just think of the batteries they saved!