Adobe's whitespace triangular abstract A in the red box logo is an evolutionary design based on the 1982 Adobe logo by Adobe Systems Graphic designer Marva Warnock who designed the company's first corporate identity.
The 1982 Adobe unwarily offered a glance of what the future and current Adobe logo would look like. The first letter ‘A’ in the logo got stylized further and was set inverted in whitespace into the famous red rectangle. The logo sets an example of how a company extends and respects its own graphic history.
This type of stylized ‘A’ can also be seen in other logos like the Paccar owned truck building company DAF or Dutch lighting magazine OAK.