This has come up in chat a few times, but no one has apparently feedbacked it yet: many of the building blocks produce loops that are non-ideal from the start. The sheet-sheet loops are the worst - only 3 of the 7 are good. No wonder some people don't find the blueprint tool helpful. Here is a list of which ones are ideal and not ideal. This is with sheets and helices already made with ideal SS before adding building blocks, and with an adjacent sheet providing sheet bonds before adding building blocks involving sheets.

Helix-Helix:
1. blue: ideal
2. green-blue-blue: ideal
3. blue-blue: ideal
4. green-blue: ideal
5. blue-red-blue: ideal

Helix-Sheet:
1. green-blue: ideal
2. green-blue-red: ideal
3. blue-red: ideal
4. blue-red-red: NOT ideal
5. (not a building block) no loop, straight from helix to sheet: ideal

Sheet-Helix:
1. red-blue: ideal
2. blue-blue-blue: ideal
3. green-blue-blue: ideal
4. (not a building block) no loop, straight from sheet to helix: ideal

Sheet-sheet:
1. green-green: ideal
2. blue-red-red-green-blue: NOT ideal
3. yellow-red: NOT ideal
4. red-red-red-green: ideal
5. blue-green: ideal
6. red-green-red-blue: NOT ideal
7. blue-red-red-yellow: NOT ideal