What shape characterized the faintest and reddest galaxies observed in the HDF and HUDF images?

Small and irregular, appearing like "toothpicks" or interacting in "box matches."

A major discovery from studying the deepest fields was the profound difference in morphology between ancient and modern galaxies. The galaxies that appeared farthest away, characterized by being the faintest and reddest in the images, were overwhelmingly not the structured spirals or massive ellipticals seen in the local universe. Instead, these primordial galaxies were typically small and irregular in shape. Detailed descriptions often compared their appearance to structures like 'toothpicks,' 'links on a bracelet,' or galaxies violently interacting in what was termed 'box matches.' This visual evidence strongly supports the hierarchical model of galaxy evolution, suggesting that large, organized galaxies grow over cosmic time specifically through the repeated merger and coalescence of these smaller, less structured clumps.