the massive axe was blunt , the emeralds fractured shards of glass , the plate thin iron hammered flat over a scaffold , the knight 's prominent knees immovable , solid , fixed like all his joints , without pivots or hinges so that he could not have stood had any petitioner challenged his authority , questioned his power to wield boons and curses , mocked the frailty of his expression behind the patriarchal sternness of his mask .