The Wimpy pattern is a
synchronous four ball trick in which the balls are simultaneously thrown
between hands, such that they would, theoretically, overlap in the middle.
To avoid collisions when actually running the pattern, the balls are
generally thrown at slightly different heights, so that one hand always
throws its ball slightly higher than the other.
To learn the Wimpy pattern, it is best to start with one ball in each hand. Then, simultaneously throw the two balls along a Cascade like path to the other hand, making sure to throw one slightly higher to avoid collisions.
This is pretty much the only intermediate step to learning the Wimpy. After you have the two throws above mastered, just start with two balls in each hand and make a second set of throws after the first set are past their peak. The Wimpy pattern with any number of balls is generally easier than the corresponding fountain pattern, so learning the Wimpy with four balls should not be too difficult.