class ArgComp_coord 
{
    <: coord;
    node(Root).cat = value(ArgComp);
    - coord2::ArgComp_coord_block; Coord2 = coord2::SComp;
    node Coord2: [cat: ArgComp, type: std, bot: [arg: $arg]];
    - coord3::ArgComp_coord_block; Coord3 = coord3::SComp;
    node Coord3: [cat: ArgComp, type:std, bot: [arg: $arg]];
    node(Foot).bot.arg = $arg;
    node(Foot).top = node(Root).bot;
}