Desk in closet needs more top space, a slide out will work.
Step 1: First Stage Extension
Note extension first stage.
Step 2: Second Stage Extension Ready to Be Lifted
Second stage with piano hinge ready to be lifted.
Step 3: Both Stages Complete
Note both stages in open position and clipped to door.
Step 4: Clip to Door for Support
Second stage clipped to door or other structure. Use removable leg if no structure exists.