For quippy superstar engineer Cal Henderson, the fellow who has kept Flickr from crashing all these years, attendance at Yahoo's Hack Day developer event was all but mandatory, since he works there. But what attracted Pownce cofounder Leah Culver, Henderson's ex-girlfriend? A Valleywag tipster's spy camera caught the two of them hard at work, laptops side by side. All business, clearly — until it came time for the awkward parting hug, and perhaps more. "Looked like they were kissing in the pic with him holding her, but can't say it looked very enthusiastic or romantic," our tipster analyzes. Full photos below, so you, too, can interpret the body language in the comments.S S More spy photos? Send them in.