My guitar teacher showed me last lesson 5 scales in A minor or C-major(that´s almost the same, i think) and said with these scales or patterns, i can improvise all that is possible. And i think i got this, but i don´really know if it´s true. So i think: If i can do these 5 patterns in C major i can jam allong the whole fretboard. so if i want to jam in for example G major i have to put all these patterns so many tones up or down as necassary.