A L L G G G E E E E B B B B B R R R R A A A I I C Look at a sample path: A / L L \ G G G \ E E E E \ B B B B B / R R R R / A A A \ I I / C That particular path could be represented by LRRRLLRL. Or you could stay along one of the edges: A / L L / G G G / E E E E / B B B B B \ R R R R \ A A A \ I I \ C That path could be represented by LLLLRRRR Every path could be represented by a distinguishable permutation of LLLLRRRR. And every distinguishable permutation of LLLLRRRR would represent a different path. You can look at that either of two ways: The number of distinguishable permutations of LLLLRRRR and calculate it this way: So the answer ispossible paths. Or we could say there are 8 positions in each distinguishable permutation of LLLLRRRR, and we choose 4 or those positions to place the L's in in 8C4 ways and the other 4 would be filled with R's in only 1 way. So the answer in that case would be simply the combinations of 8 things taken 4 at a time. 8C4 = 70. Edwin