C Ionian

Chord Progression:  

I (C major) V (G major) vi (A minor) IV (F major)

I. C major
C, E, G
E4B3G3D3A2E2CCCCCCEEEEEEEEGGGGGGG
V. G major
G, B, D
E4B3G3D3A2E2GGGGGGGBBBBBBBDDDDDDD
vi. A minor
A, C, E
E4B3G3D3A2E2AAAAAAACCCCCCEEEEEEEE
IV. F major
F, A, C
E4B3G3D3A2E2FFFFFFAAAAAAACCCCCC