Yeah, crates & barrels. The like
And, in case you ask "why use colliders instead of small bullet-blocking polygons?":
• colliders are invisible; polygons aren't
• in very thin bullet-blocking polygons, projectiles flying at very fast speeds can still get through. Colliders absolutely stop every single projectile, and also trigger grenades to detonate immediately (grenades simply lay on bullet-blocking polygons).
• it's very easy to place colliders as opposed to bullet-blockers, and since they always maintain the same form (you can change their size by changing the # in the Radius box, in the Palette window), you can quickly reproduce the effect among many sandbags or such
But Boxo uses tall bullet-blockers to prevent spraying (very thin, long rectangles, basically—see the center of his ctf_Dropdown2). They're both useful.
