The Bed Tent That Makes Noon Dark Enough for Sleep

The whole shelter is free standing and needs nothing fixed to the bed: it rests on the mattress itself, and flexible ribs pop an opaque dark shell into a tunnel just under four feet tall at the crown, enough headroom to sit upright inside, with a zip door on each of the four sides and two windows. The panels are what do the work, holding daylight out of the space while the rest of the house is lit, and the whole shell folds flat into a carry bag when the bed goes back to being a bed.