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Recently a suggestion has been made that standard textbook representations ofhypersurfaces of simultaneity for the travelling twin in the twin "paradox" areincorrect. This suggestion is false: the standard textbooks are in agreementwith a proper understanding of the relativity of simultaneity.Comment: LaTeX, 3 pages, 2 figures. Update: added new section V and updated  reference

A note on Dolby and Gull on radar time and the twin “paradox”