Here is spirulina powder in water, after a few minutes of soaking. Dry spirulina powder looks rather boring under the microscope - just nondescript green blobs. But add some water and they appear to self assemble into macaroni-like structures, some of which form nearly closed loops. Thanks to John Alan Elson for his web page on spirulina powder under a microscope, which inspired us to try it ourselves.
Equipment used: AmScope M150C microscope at 400x magnification