Interlocking

Spirus
Square Face
Square Rod Dodecaplex
Square Target
Squirrel Cage
Stacked Sticks
Stand By Cube 2
Star Ball Burr
Star Box Burr
Star Break
Star-TIC 1
StarLock
Stellar Burr
Stick it box
Stickman No. 9 Snowflake
Sticky Stack or Sticks
Stitch