Draw a closed loop passing through centres of all cells horizontally or vertically. Cells with the same letter all have the same appearance as to how the loop enters and exits the cell. Cells with different letters have a different appearance.
History of the puzzle
First appeared on Zagreb Open 2012. Author of the puzzle was Bram de Laat (Netherlands). 
The name of this puzzle is in reference to Gemini Block by Naoki Inaba (Japan). 
Appearances in the past WPCs
- WPC 2017/Round 12 by Amit Sowani