A connection device may include a first side support, a second side support opposite the first side support, a first guide and a second guide opposite the first side support. The first guide and second guide connect the first side support to the second side support. The first guide, second guide, first side support and second side support define at least one cavity shaped to accept an upright beam. A plate may extend between the first side support, the second side support, the first guide and the second guide, in which case the plate, first guide, second guide, first side support and second side support define two cavities shaped to accept two upright beams. One or more of the first guide, second guide, first side support and second side support may include a plurality of side attachments that define side connection area(s) shaped to accept a lateral beam(s).