R>        crossbeam::scope(|scope| {
R>            let chunk_len = (cubes.len()/thread_cnt as usize)+1;
R>            for (ch_idx, chunk) in cubes[..].chunks_mut(chunk_len).enumerate() {
R>                let start = ch_idx*chunk_len;
R>                scope.spawn(move || {
R>                    ...
R>                });
R>            };
R>        });
R>