The last variation posted is a combination of both Variation 2 and Variation 3. In the rhythm, 1 and uh 2 and uh 3 and uh 4 and uh, go upwards in the chromatic scale while striking the note a half step below the primary note.
Xylophone Exercise Variation 4
Variation four is the exact opposite of the previous one. Instead of playing a half step lower every 2nd triplet, you will play a half step higher (C, C#, C; B, C, B; etc.)
Xylophone Exercise Variation 3
With the third variation, as you go upwards chromatically you will be striking a note a half step below the main pitches every 2nd triplet (C, B, C; C#, C, C#; etc.). This is done in 16th triplets upwards and a major scale down in 16ths.
Xylophone Exercise Variation 2
In the second variation you go up chromatically but in a 32nd note rhythm (1 and uh, 2 and uh, 3 and uh, 4 and uh) and back down a major scale.
Xylophone Exercise Variation 1
This is the first variation of the PSG exercise. It's the exact opposite of the original. Down chromatically and back up in a major scale.