This bug will occur when having speed 15 and holding right click to place a solid block on your Y coordinate and holding S slightly after holding right click. Then wait a moment and while still moving, hold shift and keep backing up. Blocks will start to pile on top of the last block that was able to be placed. Video files: https://drive.google.com/a/cm201u.org/file/d/1dmK6kvWeADpptXLBrEcfeiCUugfL4IMK/view?usp=drivesdk   https://drive.google.com/a/cm201u.org/file/d/1-4z-Z99fkQKjm_8Qfr2hZ8Y-Z8jaxy6d/view?usp=drivesdk