Kids love furniture forts. Some of those kids grow up to be architects. And some of those architects, remembering their love of blanket ceilings and sofa cushion walls, are applying their expertise to the long-neglected academic study of furniture forts. Members of the architecture firm BUILD have taken to the company blog to offer a "critical analysis" of kids' living room creations. And criticize they do, offering grades on 20 different creations. Here's a sampling of BUILD's assessments and what they reveal about how to build the perfect fort. Click through for photos of the forts: Part 1, Part 2.

• What Gets an A+  Not much; the team handed out only two. They favor big, open spaces and the use of support structures to allow for high ceilings. Blanket roofs propped up with a broom handle are key. Soft, complementary colors are important.

The clear reference to pole barn framing resonates with us and we found amusement in the tongue-in-cheek dual structural system. The clever siting of the project is finished nicely with a deliberately draped, light-weight roof structure. A warm, modern color palette gives the project a handsome and approachable street front.

A brilliant synergy between the weighted foundation and the light tensile structure, this project impressed us with its attenuation of structure and bright interior spaces. The courtyard and formal entry are also well thought-out and provide a clear means of way-finding.

• What Gets an F  Even less; only one F was handed out, to a pair of sleepy-looking boys sitting on a pile of cushions on the floor. "Good God gentlemen, you’re a mess! You need walls, you need a roof. Get to work man!"

• Separate Indoors From Outdoors  The architects praise "a clear delineation between indoor/outdoor space with a design focus on protection through the use of barrier" and "fully sheltering the interiors ... while an entire façade remains open to the exterior." In one of the only A+ winners, "The courtyard and formal entry are also well thought-out and provide a clear means of way-finding."

• Soft Roof  While the team approves of one fort's use an entire upturned sofa as a roof, they tend to strongly prefer blanket roofs over cushion roofs. The challenge, then, is how to prop up the roof without letting it sag into the interior.

• The Mayan Element  They handed a C+ to an otherwise doomed structure (it lacks a roof or sturdy walls) for its Meso-American influence.

Mayan in geometry but American barcalounger in function, this hybrid design allows for both formality and comfort. To our disappointment, the plan design could have taken better advantage of the site opportunities and, ultimately, the fact that a roof structure was not included in the programming detracts from the overall project.

• Colors Matter  The team looks for two-tone block colors and abhors patterns. "A warm, modern color palette" gets an approving nod while the team holds their noses at "an inconsistent material palette" and, in one case, a "poor choice of plaid."

• Look to Europe  The architects raved about European influences, which are more visible than you might expect. They saw "the saw-tooth roof structures of industrial Europe" and "the classic Tuscan stone towers of Italy," not to mention a "rare example of cathedral buttressing."

Want to add to this story? Let us know in comments or send an email to the author at mfisher at theatlantic dot com. You can share ideas for stories on the Open Wire.