ไม่มีใครรู้ว่ากีฬาเหล่านี้เล่นบนสนามที่มีตาข่าย, เล่นกระทบกำแพง,หรือทั้งสองอย่าง
Người ta không biết liệu những môn thể thao này được chơi trên sân có lưới, dựa vào tường hay cả hai.
หนังสือที่มีกฎซับซ้อน ชี้แจงความเป็นไปได้ในการกำหนดรูปแบบของกีฬานี้
Một cuốn sách với những quy tắc phức tạp Làm rõ khả năng xác định thể thức của môn thể thao này.