Distract them somehow until you're ready.


Don’t allow for too much time to pass between when you apply the color and when you want the rainbow to appear, as the paint may dry over time.
 Place first color toward the end of the wiper blade (toward the outside) and then work your way toward the middle.









Create a 1” to 2” (2.5-5cm) line with each color. You want enough color to create the rainbow, but without being overly suspicious or within the driver’s sight line.
For the sake of safety, only add the colors to the passenger side window, so that the driver can still see.
 You want the rainbow colors to blend once the windshield wiper has been activated, so the colors should be placed close together.
Choose a time when you can apply color to the windshield without your friend knowing what you're doing.
Squeeze a line of color directly on top of the windshield wiper, on the windshield.
Add the next color directly next to the previous color.
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