def thicker_blocks(blocks, delta=1):
    """Takes a list of blocks and thickens them 
    by an amount equal to delta"""
    newblocks = {l: idm for (l, idm) in blocks}
    for b in blocks:
        for dx in range(-delta, delta + 1):
            for dy in range(-delta, delta + 1):
                for dz in range(-delta, delta + 1):
                    l = b[0]
                    newblocks[(l[0] + dx, l[1] + dy, l[2] + dz)] = b[1]
    return list(newblocks.items())