We've seen children's large-toy castles for playing inside of; older ones might be made of cement (homebuilt), manufactured ones out of die-cast plastic.
The "Plush Castle" is made from blocks of soft foam with plush faux-fur on the outside; assembled with a couple of artfully hidden velcro strips, the castle is big enough for grown-ups to crawl into and snooze, occasion permitting.-- FlyingToaster, Dec 26 2008 Soft-side "Legos" Soft-side_20_22Legos_22Ahem? [phoenix, May 10 2009] Exploratorium Tactile Dome http://www.explorat...ile_dome/index.htmlRelated structure [csea, May 11 2009] How about tabs and slots, with the velcro inside the slots?-- pertinax, Dec 26 2008 We had plush building blocks, about 6" cube. I'd get my dad to spend hours building up a wall, then just as he set the last brick into place, I'd jump on it and knock it all down and make him do it again.
Ours didn't have velcro, but with sufficient skill it wasn't necessary.-- snoyes, Mar 18 2009 It would be nice if it came with a means for periodic weighing, so one could track the added mass of dust mites over time.-- bungston, Mar 18 2009 [21Q] "Like this only bigger" and covered in fur and made of foam... and *lots* bigger, think 5-6 foot high/wide/deep, big enough //for grown-ups to crawl into and snooze, occasion permitting//-- FlyingToaster, Mar 19 2009 How about a false wall?-- bluebeaversscrubbingourfloors, May 10 2009 [ph] well I've envisioned rather large cube/box shapes in the one to two foot sized region, but you might want to look at [snoyes] comment here. I've thought up a better bonding mechanism though: use magnetic plates under the plush made of the same material in some refrigerator magnets (rubber with impregnated iron filings(?)).-- FlyingToaster, May 11 2009 random, halfbakery