lib/map/ellermaze.js
function addToList(i, L, R) {
    R[L[i + 1]] = R[i];
    L[R[i]] = L[i + 1];
    R[i] = i + 1;
    L[i + 1] = i;
}
function addToList(i, L, R) {
    R[L[i + 1]] = R[i];
    L[R[i]] = L[i + 1];
    R[i] = i + 1;
    L[i + 1] = i;
}
function addToList ( i , L , R ) { R [ L [ i + 1 ] ] = R [ i ] ; L [ R [ i ] ] = L [ i + 1 ] ; R [ i ] = i + 1 ; L [ i + 1 ] = i ; }
Join lists with "i" and "i+1"
Join lists with i and i + 1