When I was striving to increase my knowledge of the fingerboard back in 1976 I built a prototype of a device which would allow me to see any notated pitch on the fingerboard in all places at a glance. One of the confusing aspects of playing stringed instruments is that notated pitches can show up in more than one place. For example, middle C is found in 5 different places on the guitar!
My first prototype was something of a failure in that it didn’t give me enough flexibility. (I wish I had a photo of Oracle I, but I was a poor college student at that time living in a 16 foot Boles Aero trailer.) After the failure of that first device I built a better box. It still isn’t perfect, but it does allow me to visualize any interval combination, chord, scale, or arpeggio in every position and for every key! This device gave me a level of insight that has served me well for many decades. I have discovered so much from just typing in different note combinations, then using the sliders to isolate a particular region. To my knowledge this is the only one in existence.
I owe a great deal to this device and much of what I’m sharing on this website can be traced directly back to my time spent with Oracle II.