Having struggled all day with dying laptops, dying software, a complete inability to understand VAT rules on intra-EU software downloads (except Ireland), and Adobe Creative Cloud (about which my opinions had better remain unexpressed), I have given up trying to do work and present…
That’s a page that allows you to put in the gate dimensions and get out the required hinge offsets and angles to make the gate sit neatly, so it is vertical both when closed and when fully open.
That page still needs some extra help-features to explain just how it works, but it seems OK as far as it goes. It was vastly less work than the birthdate calculator!