T-SPINS · LESSON 4 OF 6
STSD and Fractal
AFTER THIS GUIDEYou can show how the first Double exposes the second slot, and tell a connected chain from two unrelated TSDs.
Two Doubles must share a construction.
STSD and Fractal both produce connected T-spin Doubles, but they are different geometries. The useful question is not “can I make two spins?” It is “what exact slot does the first clear leave for the next T?”
A common STSD uses a compact arrangement around a tall opening, often shaped with J and L. Fractal layers another TSD above an existing TSD base. It can make use of building time while T is late, but it also stores height and needs two Ts to finish.
Do not force Fractal on an empty board simply because it is the selected mode. Establish a playable stack, find a suitable lower TSD, then check whether the visible non-T pieces can extend it without burying unrelated holes.
You may see only one of the required Ts. That is not a promise the second arrives immediately. Keep enough room for the intervening pieces and retain an ordinary clear as a way out. In competitive play, incoming pressure may make the first safe Double preferable to the full extension.
Erase the first two rows in your head
Compare the untouched structures
The first frames mark the first T with dashed cells. Notice that STSD and Fractal do not have interchangeable cavities. These diagrams explain the clear sequence; they do not animate construction or prove an input path.
Place and clear the first T
Advance each diagram twice. Look at the cells that survive and move down. Those cells form the next slot. If you cannot explain that change, return to the first frame.
Resolve the second Double
Advance through the second T and clear. Now look beyond the chain: the remaining blocks still need a plan. “Two Doubles complete” does not mean the surface has repaired itself.
Clear sequence only: the dashed cells mark the first T. Construction and the rotation path are not animated.
The first T completes two rows.
After the first Double, the same structure leaves a second T slot.
The second T completes the next two rows.
Both Doubles are complete. The remaining blocks still need to be managed.
Clear sequence only: the dashed cells mark the first T. Construction and the rotation path are not animated.
The first T completes two rows.
After the first Double, the same structure leaves a second T slot.
The second T completes the next two rows.
Both Doubles are complete. The remaining blocks still need to be managed.
Common mistakes
Calling any two TSDs a Fractal
The second slot must follow from the connected construction. Building an unrelated TSD later is ordinary continued play.
Extending without accounting for both Ts
The board must remain playable while you wait. A second slot is not useful if the queue forces you to seal its entry.
Learning only the attack frames
Study the after-clear frames just as carefully. They explain both the chain and its cleanup costs.
TAKE IT TO THE BOARD
Compare one STSD and one Fractal
- Open STSD with Gravity Off and NEXT 5. Inspect one full Double-to-Double sequence; predict the second slot before the first clear.
- Switch to Fractal and repeat. Start by observing the base rather than trying to copy the STSD shape.
- After each chain, make three cleanup placements. Write one sentence describing how the two structures differ.
What counts as progress? You identify the second slot before clearing and know which parts of the structure must survive.
Open practice ↗Opens the mode. Set Gravity and NEXT yourself; your current settings are kept.
Keep these terms nearby
NEXT IN THIS PATH
Choosing a stacking system
Compare LST, ST and DT by the decisions they ask you to make.
Read the next guide →Further reading
For setup variations and additional examples, see FOUR: Fractal. The practice task here is original to Stacking Lab. For setup variations and additional examples, see FOUR: STSD. The practice task here is original to Stacking Lab.