Possible Clues:

• Not equilateral or isosceles
• Opponents in game involved in sequence played with different sides
• Kind of triangle with different side lengths
• Triangle with three unequal sides
• Climb north face of Everest made up of different sides
• Get to the top on Tyneside?
• Like a triangle with unequal sides
• Like a triangle with three unequal sides
• Having sides of different lengths, as triangles go
• (Of triangle) having three unequal sides