My wife bought a robotic vacuum cleaner. She named it Hazel. The machine does a very good job of vacuuming. It works for around two hours to do the whole house, recharging two times. When its power becomes low, little round Hazel makes its way to the charger and glides into position.
(I just had a thought: My wife named several machines after women. The GPS she bought for me several years ago she named Eleanor because it was bossy, like Franklin Roosevelt’s wife. The on-board GPS in my wife’s Ford Flex is called Lucy, because it often has some ‘splanin’ to when it shows an illogical route and then commands the driver toward that route instead of going a commonsense way.)
Hazel is persistent. Encountering an obstacle, it turns 90 degrees, moves a few inches, turns back to its original direction, attempting to move around the obstacle. The robot will do that until it is successful in going the direction it wanted in the first place. Just visualize a couch, with the robot moving, turning, moving, again and again until it clears the obstacle.
The first time we used the machine, it stopped after about 20 minutes and announced it was not on a level surface. It asked to be leveled. It had dropped into the sliding door slots. Later, it got underneath the bed and could not find its way out. Then it vacuumed the shower, but could not climb back into the bathroom.
Our two dogs put up with the robot, but they do not like it. When Charlie sees the robot, he goes somewhere else.
Victor, the larger dog, watches the machine make its way across the floor. The look on his face shows he thinks Hazel is a malevolent creature, intent on doing harm. Victor keeps his place on the floor until the robot is moving directly toward him and is close, and then he gets up and goes to the safety of a cave, i.e., a bedroom.
Hazel always finds him.
(Edited to fix a not-paying-attention mistake of calling the robot the wrong name.)