Step 1: You will need.
3 sets of two fly swatters (in a variety of fun colors)
For coasters #2:
Four magnifying glasses
Pliers and/or hacksaw
For coasters #3:
4 rubber sink mats
Step 3: Coaster 1 - Step 2
For round fly swatters, simply cut along the circumference.
Step 5: Coaster 2 - Step 2
If you have a magnifying glass that is made from molded plastic and the handle can't be unscrewed, then you can remove the handle by sawing it off.
Suggestion: You can increase the magnification by placing the circles on plastic pegs to raise them slightly off the table. I didn't do this because I found it more aesthetically pleasing without this.
Step 7: Step 2
Another variation that turned out nice was cutting out 4x4 squares on the square-patterned part.
A possible variation is to paint the outer ring of the circle black or painting in every other square black.