When he was a U.S. Supreme Court litigator, Chief Justice John Roberts famously prepared for oral arguments by writing his main points on index cards and shuffling them to ensure he could smoothly answer questions regardless of the sequence they arose.

Attorney Athul Acharya has created an app to moot him that’s based off that basic method—and a video titled “RoboJudge!” showing the technology in action attracted the attention of appellate lawyers on Twitter last week.