Dreamroom is an other in The Punished, a mod for The Binding of Isaac.
Once Isaac touches the Dreamroom's bed, he enters a lucid dream and is transported to the Dreamscape.
When this happens, all pickups/items in the chalk drawings are consumed.
Inside the Dreamscape Isaac will find an Old Chest, containing a pickup based on those consumed:
• The pickup inside the chalk chest is used as the base (the resulting pickup will be of the same category and subtype, if the other two chalk drawings are empty).
• If a pickup is inside the chalk circle, its type determines the type of the resulting pickup.
• The number of pickups inside the chalk Spindown Dice determine how many times the resulting pickup will be spun down before being generated.
Examples
If the chalk chest contains III - The Empress and the other two drawings are empty, then the Dreamscape's chest will have III - The Empress.
If the chalk chest contains III - The Empress (which is the card with id=3), the chalk circle contains an item, and the chalk Spindown Dice is empty, then the Dreamscape's chest will have Spoon Bender (which is the item with id=3).
If the chalk chest contains III - The Empress (which is the card with id=3), the chalk circle contains an item, and the chalk Spindown Dice has 2 pickups, then the Dreamscape's chest will have The Sad Onion (which is the item with id=1).