def METHOD_NAME():
    '''
    IOB33S: main IOB of a diff pair
    IOB33M: secondary IOB of a diff pair
    IOB33: not a diff pair. Relatively rare (at least in ROI...2 of them?)
    Focus on IOB33S to start
    '''
    db = Database(util.get_db_root(), util.get_part())
    grid = db.grid()
    for tile_name in sorted(grid.tiles()):
        loc = grid.loc_of_tilename(tile_name)
        gridinfo = grid.gridinfo_at_loc(loc)
        sites = []
        for site_name, site_type in gridinfo.sites.items():
            if site_type == 'IDELAYE2':
                sites.append(site_name)
        if len(sites) == 0:
            continue
        sites_y = [
            int(re.match('IDELAY_X[0-9]+Y([0-9]+)', site).group(1))
            for site in sites
        ]
        sites, _ = zip(*sorted(zip(sites, sites_y), key=lambda x: x[1]))
        if gridinfo.tile_type[0] == 'L':
            int_grid_x = loc.grid_x + 3
            pad_grid_x = loc.grid_x - 1
            int_tile_type = 'INT_L'
        else:
            int_grid_x = loc.grid_x - 3
            pad_grid_x = loc.grid_x + 1
            int_tile_type = 'INT_R'
        int_tile_locs = [
            (int_grid_x, loc.grid_y),
        ]
        pad_gridinfo = grid.gridinfo_at_loc((pad_grid_x, loc.grid_y))
        pad_sites = pad_gridinfo.sites.keys()
        pad_sites_y = [
            int(re.match('IOB_X[0-9]+Y([0-9]+)', site).group(1))
            for site in pad_sites
        ]
        pad_sites, _ = zip(
            *sorted(zip(pad_sites, pad_sites_y), key=lambda x: x[1]))
        if not gridinfo.tile_type.endswith("_SING"):
            int_tile_locs.append((int_grid_x, loc.grid_y - 1))
        assert len(sites) == len(int_tile_locs), (
            tile_name, sites, int_tile_locs)
        assert len(sites) == len(pad_sites), (sites, pad_sites)
        for site_name, pad_site, int_tile_loc in zip(sites, pad_sites,
                                                     int_tile_locs):
            int_tile_name = grid.tilename_at_loc(int_tile_loc)
            assert int_tile_name.startswith(int_tile_type), (
                int_tile_name, site_name, int_tile_loc)
            yield int_tile_name, site_name, pad_site