How we cite our quotes:
Yet looks he like a king. Behold, his eye,
As bright as is the eagle's, lightens forth
Controlling majesty. (3.3.4)
Despite being trapped by Henry Bolingbroke's men, Richard still looks like a king, to York's eyes anyway. But York importantly mentions that the impression of power is just that – an impression, and a deceptive one. Two lines later, he regrets that "any harm should stain so fair a show!" By using the word show, York is highlighting how insubstantial Richard is and always has been.
No deeper wrinkles yet? Hath Sorrow struck
So many blows upon this face of mine
And made no deeper wounds? (4.1.10)
After Richard loses his crown, he looks in a mirror and expects to see that his face has aged as a reflection of his sorrow and grief. This is evidence that Richard constantly confuses surface and substance. Here he confuses his face with his experience. It seems logical to him that his face should have wrinkles to provide evidence of his suffering.
O, flatt'ring glass,
Like to my followers in prosperity,
Thou dost beguile me. (4.1.10)
As he continues to look into a mirror, Richard is surprised to find his face basically unchanged. Feeling that he's been deeply transformed by losing the crown, it troubles him that his face refuses to show his suffering, to provide an honest reflection of his reality. He accuses the glass of "flattering" him, of making him look healthier than he really is – much like his advisers did when he was still in power.