Almost any 3d printer can print this three color Flag of the United States with just two simple color changes.
The white layer prints first, then the red stripes, then the blue field, and the white stars show through the holes in the blue field.
.25 layer height x .35 nozzle
This is a 3mm print with color change every mm; i.e white background for 1mm, red stripes for 1mm, then the blue field for 1mm.
I used a .25mm layer height, so each color is 4 layers thick.
I used ColorPrint by Prusa3D to set a color change at layer 1.25mm and 2.25mm
Making a wavy flag
To make the flag "wavy", I followed these steps. Do so at your own risk because it involves very hot water to bend the finished print.
BE CAREFUL WITH HOT WATER IN THE FOLLOWING STEPS.
CAUTION: DON'T TRY TO MOVE A PLATE FULL OF HOT WATER!!!
I filled a microwave safe plate with just a few millimeters of water, then boiled the water in the microwave for about 35-45 seconds.
Leaving the plate in the microwave, I carefully used a pair of tongs and placed the finished print in the boiled water for just a few seconds, then fished it back out with the tongs.
I let it cool for a second or so then I used my hands to mold a simple wave in the flag.
You should probably use a pair of rubber gloves.