Unzip a resealable plastic bag. Place it on your work surface.
Fold a paper towel into quarters. Fold the towel in half again. Slide the paper towel into the resealable plastic bag with the opening of the fold facing up.
Fill an eye dropper with water. Squirt the water onto the paper towel to make it wet without excess water accumulating in the bottom of the plastic bag. Use more than one eye dropper full of water, if necessary.
Drop two bean seeds into the middle of the wet paper towel. Position the seeds so they're about 2 inches apart.
Zip the resealable plastic bag to create a greenhouse effect inside the bag.
Bring the plastic bag with the towel and bean seed to a window that gets sun for six to eight hours per day. Tear off a piece of masking tape about 3 inches in length. Place the tape horizontally on the center of the top of the bag and adhere it to the window.
Unzip the end of the bag enough to fit the tip of the eye dropper into the opening. Add one eye dropper full of water to the bag every three or four days to prevent the paper towel from drying out.