It's a pretty simple explanation. Blockland is client sided, yet it runs on Torque. Roblox has partial real-life physics built into pretty much everything, but it runs on Lua. In Blockland, if you build some bricks in an about-to-fall position, nothing happens. But in ROBLOX, if you build a bridge with bricks stacked up in the starting pont, the torque will increase on the bridge, and eventually fall because the starting point is the only point where there are bricks stacked up.