Stellar radius versus stellar mass. The green, blue and red pale dots indicate sub-samples defined using observable properties from the local Universe. Stars represent our likely infant GC candidates and triangles our proto-UFDs. The magenta circles and cyan squares are high redshift observations from Vanzella et al. (2017) and Bouwens et al. (2017) respectively. For the Bouwens et al. (2017) data, we have taken objects from their Table 2 which had a radius < 50 pc including errors.