For low level solos, a player (wanting to be quiet in a library perhaps) could have a bookmark page with random dice arranged in large groups, say 9 or 12. A pencil is dangled over the page, eyes closed and then placed on the page like pin-the-tail-on-the-donkey. Where the pencil lands is the group of virtual dice rolled. If the player only needs the values from four dice he simply reads from that randomly chosen group the first four dice. (Whether the player reads across or down is up to them as long as they are consistent with themselves and don't cheat.) It's no substitute for real dice but it may work to a point.