2025’s Substrates Workshop garnered a wide spectrum of approaches to this nascent field of software construction. As the call for this year’s workshop acknowledged, these could be fitted onto one or more dimensions, reflecting different modes of enquiry and the interests of different research communities. Articulating these dimensions and trying to place the work of our contributors along them might help clarify the relationships between the work of different groups and how they can complement each other, and how they could be scheduled as part of the work of a larger research programme.

This short paper makes some highly provisional attempts to identify such axes and place some relevant work on them. It should be considered as a spring-board for discussion and mutual illumination rather than a finished taxonomy.