Juxtaposing austere architectural details with oddball visual accents evokes a wicked sense of play. That spirit infuses the Oakley campus: a zip line once ran from the top of a building to a waterfilled ditch; in the back, a giant fire pit anchors a muddy tradition called Water Fest; despite repeated fines from the local homeowner’s association, a skull and cross bones often waves from the building’s flagpole.