You may enter the box and wait when you want to turn right, and are only stopped from doing so by oncoming traffic, or by other vehicles waiting to turn right.
Cewch fynd i mewn i’r bocs ac aros pan fyddwch eisiau troi i’r dde, ond does dim modd i chi wneud hynny oherwydd traffig yn dod y ffordd arall, neu gan gerbydau eraill sydd hefyd eisiau troi i’r dde.