Project: canvas
Task (moderate): Randomly spawn items in the middle of pipe gaps with item size 20*20. Spawn rate controlled by 'store.randomRate' (default 0.25, variable). Items move with pipes and store in pipe object with properties (x, y, type, collected). Item 'Shield': appears as filled green diamond, grants protective shield effect. When collected, displays spiked gear ring around bird (lineWidth 5, radius 1.5 * birdWidth) and sets 'isProtected' and 'shieldEndTime' in store. Shield provides 5 seconds invincibility, ring flashes during final second. Shield giving the bird invincibility without losing lives. Collecting another Shield while active resets duration to 5 seconds.