By Jack Chelgren | Special Projects Intern   When Tree Swenson, the executive director of Hugo House, introduced Kay Ryan for a lecture on rhyme last week, she noted the delightful sense of “hidden treasure” lurking in Ryan’s work. That treasure, Swenson said, was rhyme: glowing little ingots of resonance between words. It’s an apt observation. Take these lines from “All Your Horses,” published recently in Poetry: Say when rain cannot make you more wet or a certain thought can’t deepen and yet you think it again: you have lost count. A larger amount is no longer a larger amount.