Other physically possible supertasks have been suggested. In one proposal, one person (or entity) counts upward from 1, taking an infinite amount of time, while another person observes this from a frame of reference where this occurs in a finite space of time. For the counter, this is not a supertask, but for the observer, it is. (This could theoretically occur due to time dilation, for example if the observer were falling into a black hole while observing a counter whose position is fixed relative to the singularity.) Gustavo E. Romero in the paper 'The collapse of supertasks' maintains that any attempt to carry out a supertask will result in the formation of a black hole, making supertasks physically impossible.