Here, Jon demonstrates the C lydian scale, and it's characteristics: C Lydian is a G major scale starting from its 4th degree (C). -C Lydian is a C major with a raised 4th degree. C Lydian is a C major pentatonic scale with a #4 (F#) and 7th (B) added. Since Lydian is the only major mode with a #4 (F# in this case), #4 is said to be the characteristic note of Lydian. If you want your solo to convey a distinctly Lydian sound, feature the #4 of the scale a lot. Conversely, avoid it if you want to be less obvious.