1.

Halve the avocados, and remove the pits. Use a large spoon to scoop the flesh from the skin of the avocados, leaving the flesh of each avocado half intact. Turn the avocado over so the hole where the pit was is facing down to the cutting board, and the avocado is situated so the long length of the avocado is running north-south. Slice an array of vertical cuts, creating thin slices of avocado, but be careful not to cut all the way to the top of the avocado. Leave a bit untouched at the top. Turn the avocado half over and fan out the slices, still keep that top bit intact. Place the fanned avocado half on a serving plate, and repeat with the remaining 3 avocado halves.