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The easiest damage-free way to hang a tapestry is with push pins. Push pins leave much smaller holes in the wall than nails or screws and are often allowed when decorating a dorm. That being said, some dorms do not allow push pins—ask your dorm advisor before using them to make sure you don't damage the wall.  Using push pins against your college's regulations can result in fees. Push pins work best with tapestries made of light fabrics. Push pins stick into drywall and wood easily and hold up over time. Plaster walls, on the other hand, are thicker and do not usually work with push pins. If your dorm has plaster walls, try a different hanging method (like adhesive hooks or velcro). Cork also works well with push pins, though having a wall made entirely of cork is unlikely. Measure the height and length of your tapestry with measuring tape. Position the 4 push pins apart at the distance you recorded. Do not push the pins too tightly into the wall yet, as you'll need to remove or reposition them as you work. Some tapestry will have tabs on each corner that you can hook on the pins, but others will need to be pinned to the wall. Remove a push pin from the wall and position the corresponding corner of the tapestry where the pin had been. Push the pin in the wall again to secure the tapestry corner, then repeat the process with the remaining 3 corners.  Push down hard on the pin with your thumb to secure it in the wall. Reposition the push pins as you work if you miscalculated the distance of the tapestry. The larger your tapestry is, the more push pins it will probably need. If your tapestry bunches in the middle or the sides, use more push pins to secure the tapestry to the wall.

Summary:
Ask your RA or dorm advisor before using push pins. Use push pins if you have a drywall or wood wall in your dorm. Stick 4 push pins in each corner of the wall. Remove 1 push pin at a time to secure the tapestry on the wall. Add more push pins if your tapestry seems to droop.