The long: Last week, the Please Touch Museum blocked out 1,100 square feet between River Adventures and the carousel by filling three soft, holey foam walls with hundreds of oversize blue foam bricks and noodles and plastic balls.

The short: Get it? Blocked out?

The demo: Three and up. (No fun for crawlers or new walkers.)

The philosophy: "Unstructured play" continues to trend. The idea, says a museum rep: "Allow [children] to use their imaginations and creativity and to also develop fine and gross motor skills." And collaborate, too.

What kids build: Forts, ball ramps, vehicles, stepping-stones, foam swords, messy piles.

My advice: Grown-ups, let 'em go. Grab a spot on a facing bench while an attentive museum staffer handles errant ball throwers, et al.

Moment to yourself: See above. (Go ahead: Luxuriate in five whole minutes of uninterrupted texting.)

Teaching moments: Thursday, Friday and Saturday the space hosts by-reservation "Learn & Play" sessions aimed at teaching adults how to teach kids to play with these toys. Attendees get $5 off admission.

If you SEPTA: 38 bus. Short walk from 40, 43 or 64 bus.

If you drive: Free on-street parking. Lot is $8.

The basics: Please Touch Museum, 4231 Avenue of the Republic, 9 a.m.-5 p.m. Monday-Saturday, 11 a.m.-5 p.m. Sunday, $17 (under 1 free), 215-581-3181, pleasetouchmuseum.org.

Lauren McCutcheon is a features reporter whose kid proved himself a devious hoarder at Imagination Playground.