Two subjects have to be at the same time in both weeks/terms

For example you have one doulbe lesson of Algebra on week A and one double lesson of Geometry in week B. The software may put them on different days, which is usually not a bad thing.

However if you want them to be on the same time in each week, because teachers might swap kids, you can create this cardrelationship:

Basivally this will say there can be max 2 periods per all weeks. If the lessons are not at the same time, they will need more periods, thus the generator has to put them together.

Notes:
- if you have just one lesson per week, you need to specify max 1 period per all weeks