ListStridedReorder

list ListStridedReorderContents(list src, list order) {
    //change the order that the elements in the groups are arranged
    integer stride = llGetListLength(order);
    integer len = llGetListLength(src);
    integer strides = len / stride;
    list temp = [];
    list out = [];
    integer i = -stride;
    do{
        temp += llList2ListStrided(llList2List(src, llList2Integer(order, i), -1), 0, -1, stride);
    }while(++i);
    do{
        out += llList2ListStrided(llList2List(temp, i, -1), 0, -1, strides);
    }while(strides > ++i);
    return out;
}

list ListStridedReorderStrides(list src, list order) {
    //change the order that the groups are arranged
    integer strides = llGetListLength(order);
    integer len = llGetListLength(src);
    integer stride = len / strides;
    list temp = [];
    list out = [];
    integer i = 0;
    do
        temp += llList2ListStrided(llList2List(src, i, -1), 0, -1, stride);
    while(strides > ++i);
    i = -stride;
    do
        out += llList2ListStrided(llList2List(temp, llList2Integer(order, i), -1), 0, -1, strides);
    while(++i);
    return out;
}

list ListStridedReorderContentsAndStrides(list src, list element_order, list stride_order) {
    integer stride = llGetListLength(element_order);
    integer strides = llGetListLength(stride_order);
    list temp = [];
    list out = [];
    integer i = -strides;
    do
        temp += llList2ListStrided(llList2List(src, llList2Integer(element_order, i), -1), 0, -1, stride);
    while(++i);
    i = -stride;
    do
        out += llList2ListStrided(llList2List(temp, llList2Integer(stride_order, i), -1), 0, -1, strides);
    while(++i);
    return out;
}


default
{
    state_entry(){
        llOwnerSay(llList2CSV(ListStridedReorderContents([0,1,2, 0,1,2, 0,1,2], [1,2,0])));
        llOwnerSay(llList2CSV(ListStridedReorderStrides([0,1,2, 3,4,5, 6,7,8], [1,2,0])));
        llOwnerSay(llList2CSV(ListStridedReorderContentsAndStrides([0,1,2, 3,4,5, 6,7,8], [1,2,0], [1,2,0])));
    }
}