Above you'll notice a ring of large blueish disks and a ring of small blueish disks. They slowly rotate, but that's only by the way. In their centers are are 2 orange disks. Try to judge whether these 2 are of equal size. Use the Up and Down Arrow keys to increase or decrease their sizes (together) until they match up. Use the space key to clear those pesky blue disks and check the size of the orange disks. Use "c" to clear the size changes
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