Funny but the word “irregular” reminds me of the London busses. Officially there should be a bus arriving every 10 minutes, at least on our route in East London, the No. 8 bus. However. you had to wait perhaps half an hour and there was no bus in sight. Suddenly three busses arrived all at once. Perhaps they had their own timetable and could not divide by ten. Oh and the young man on this bus is my youngest son. This bus was in Switzerland (advertising for the Brits) so he naturally took a ride on it.