A program which is able to simulate the work of a seven-display device
Scenario You've surely seen a seven-segment display.
It's a device (sometimes electronic, sometimes mechanical) designed to present one decimal digit using a subset of seven segments. If you still don't know what it is, refer to the following Wikipedia article.
Your task is to write a program which is able to simulate the work of a seven-display device, although you're going to use single LEDs instead of segments.