Chord vi (Six) - the submediant chord, sometimes called the 'relative minor' - is the only minor chord in the four most-likely-to-find chords in popular music - the four chords covered in the new Musicarta 'Key Chords Volume 1' keyboard home study download.
You'll recognise the I - vi sound right away - and it's an easy-to-find;chord too - only one note is different to the tonic (home chord)
This little groove drills three One-and-Six pairs - C and A minor, D and B minor, and B flat and G minor. It's a restless little groove - because it's actually in three keys - but it's good practice, both playing and listening. Good for improvising over too - try humming or groaning over it, once you can play it.
You should be able to get the riff if you walk through the MidiPiano demos and watch the hands. You can simplify the bass line lots and still not lose the feel. The riff plays at 92 bpm - for your keyboard rhythm box or sequencer.
If you like this sort of riff and would like to take a structured approach to building your chord vocabulary this year (it's March already!), check out the Musicarta Key Chords Volume 1 keyboard creativity download via the Chords tab on the main site navbar.