8.4Alberti bass

This is probably familiar from classical piano.

Instead of playing:

C-E-G

together,

play:

C-G-E-G

That is:

low-high-middle-high

Then repeat.

For Am:

A-E-C-E

For F:

F-C-A-C

For G:

G-D-B-D

This creates continuous motion while preserving simple harmony.