Better Test Tube Holders

I'm dissatisfied with the state of current test tube holders. TTHs are currently designed as plastic blocks with holes in them corresponding to the size of different test tube sizes. In the designs I have seen/used, each side of the block is a matrix of holes accommodating only one size test tube. This generally means you'll need two different holders if you are using two differently-sized tubes. In addition to this, I find it slightly inconvenient in having to line up small test tubes into each hole, especially after repeating the step countless times.

I propose that a new test tube holder be constructed that accomodates a multitude of test tube sizes and be generally easier to use. My first thought was to shape a test tube holder like grass, because many flexible grass stalks seem to provide adequate support for keeping a test tube upright, while accommodating various sizes.