A simulator for Advent of Code days 1-4. (ignore days 5-7). First look at the respective days on that site.
Put 'R' or 'L' followed by a number in the textfield, then press enter
Put an ID range in the textfield, then press enter. It will tell you which IDs in that range are invalid.
Put a row of joltage ratings in the textfield, then press enter. It will tell you what the maximum joltage is.
The grey area is a 10x10 grid. Click on a square to put a toilet paper roll there (or remove one), and press the checkbox to have the forklifts pick up the toilet paper rolls they can.