You don’t have to truck all the way over to Somerville’s Assembly Square Mall to visit a LegoLand — we’ve got one right here on Concord Avenue at Wheeler Street, where a 6-story building is going up, lego-style, with factory-made modular components. Phase I of 603 Concord Avenue (61 units + 7,112 s.f. of ground floor retail) is taking shape very quickly, as we couldn’t help but notice last weekend when the pre-fab units arrived on giant trailers via Route 2. The pre-fab mod pods were dropped off and staged along New Street, and then trailered over to the construction site next to Trader Joe’s, where a giant crane lifted and stacked them into place, just like Legos. Another 50 units will be added next door during Phase II. Bring the kids (and your hardhats).