“Can’t Be Done”:

• “You can’t stand for five minutes without moving, if you are blindfolded.”
• “You can’t stand at the side of a room with both your feet lengthwise touching the wainscoting.”
• “You can’t get out of a chair without bending your body forward, or putting your feet under it; that is, if you are sitting squarely on the chair, and not on the edge of it.”
• “You can’t break a match if the match is laid across the nail of the middle finger of either hand, and passed under the first and third finger of that hand, despite its seeming so easy at first sight.”
• “You can’t stand with your heels against the wall and pick up something from the floor.”
• “Don’t try to rub your ear with your elbow, for it will be a failure.”
• “It takes a clever person to stand up when placed two feet from a wall with his hands behind his back and his head against the wall.”

— Sam Loyd’s Cyclopedia of 5000 Puzzles, Tricks, and Conundrums (With Answers), 1914