Whiteboard
Whiteboards became commercially available in the early 1960s, but did not become widely used until 30 years later. Early whiteboards needed to be wiped with a damp cloth and markers had a tendency to leave marks behind, even after erasing the board. Dry-erase markers for whiteboards were invented in 1975.
Multi-scale fingerboard
Possibly the first modern multiscale fretboard was used on an instrument called a StarrBoard, invented by John D. Starrett in 1977. Starrett developed a tapping instrument that employs a matrix of halftones, fretted horizontally with strings spaced vertically, to allow one fingering to cover all scales. Because of the large range of notes from low B below E on a bass, to high B four octaves above, however, he needed a way to have a long scale for the low B, but a shorter scale for the high B. He simply laid out the two scales he thought would work and connected the dots.