:something that looks different from what it is:something that you seem to see but that is not really there视错觉；视觉幻象
The closer building looks larger than the farther one, but it's just an optical illusion. The two buildings are actually the same size.近处这栋楼看上去比远处那栋高大，其实这只是视错觉。这两栋楼实际上大小一样。