Hammer and Nails (1977) by Hans Godo Frabel. A "glass hammer" is a highly impractical object which an apprentice might be sent to fetch as part of a fool's errand
A fool's errandprank is a type of practical joke where a newcomer to a group, typically in a professional context, is given an impossible or nonsensical task by older or more experienced members of the group. More generally, a fool's errand is a task almost certain to fail.
Many such errands require the victim to travel some distance and request an impossible object by name; the prank will be widely known within the peer group as an in-joke, and the person they ask for the object will play along, often by sending the victim on to make the same request elsewhere.
The errand is an example of a hazing ritual, through which a newcomer gains acceptance into a group.
One type of North American fool's errand is the "snipe hunt". The hunters are typically led to an outdoor spot at night and given a bag or pillowcase along with instructions that can include either waiting quietly or making odd noises to attract the creatures. The other group members leave, promising to chase the snipe toward the newcomer; instead, they return home or to camp, leaving the victim of the prank alone in the dark to discover that they have been duped and left "holding the bag". As an American rite of passage, it is often associated with summer camps and groups such as the Boy Scouts.
New car repair staff are requested to collect fresh spark plug sparks, by catching sparks from a grinder disc using a small box. Other similar items are "diesel engine spark plugs" (diesels do not have spark plugs), "exhaust pressure bearings" or "piston returner springs".
New car salespeople are often sent to different dealerships around town to get the "lot stretcher". After reaching the new dealership, the manager informs the victim that it has been moved to another dealership across town, and the prank continues. Also amongst the vehicle related lists are "high speed air" (for tires), likewise "aerodynamic lugnuts".
A common fool's errand is to send someone to get "blinker fluid" or "turn signal fluid" from an automotive parts store.
In the pizza-making business, newcomers are told to look in the fridge for the "dough repair kit".
Another variation includes being sent to procure a "long weight" or "long stand", the idea being that the dupe will reach the shop (or equivalent source of the mythical object) and place the request. The victim is then delayed by the shopkeeper and thus receives a long wait.
Other common restaurant practical jokes include sending the new employee to another restaurant to borrow the "bacon stretcher", "lobster food", "lobster gun", a "souffle pump", left-handed tongs, the "oven key", a left-handed broom, or a "can of steam". An alternative prank is to instruct the new employee to empty a coffee machine or hot water tower of its water (the machine being connected to a water line and thus never able to be "emptied").
In the decorating and construction trade, a "left-handed screwdriver", "board stretcher", "eye measures", "hammer grease", "wall expander", "glass hammer", "striped or tartan paint", "metric crescent wrench", "bucket of grinder sparks" or "box of assorted knots" are analogous pranks. Another such errand subject, "polka-dot paint", became real in the 1950s with the development of a polychromatic paint which created a dotted effect when dry.
A lightbulb frosted on the interior was once thought to be impossible
At General Electric's NELA Park plant in the 1920s, as a joke, newly hired engineers would be told to develop an inside frosted lightbulb, which the experienced engineers believed to be impossible (previous bulbs had been sandblasted for the frosting effect, which caused brittleness). In 1925, newly-hired Marvin Pipkin got the assignment and astonished his peers by succeeding.
Electricians commonly send the "new guy" to the toolroom to fetch a "cable stretcher" or a "cordless wire"/"wireless cable".
In the United States Navy, pranks have included sending a new sailor after a "BT Punch" (a fist-punch) from a Boiler Technician who works in the Engine Room; "red lamp oil for the port running light" and "green lamp oil for the starboard running light"; a "gallon of prop wash"; and "sound-powered phone batteries". Other examples are to send the dupe on a search for a "spool of water line", a "dropped gig line", a "bucket of steam", or the infamous "ID-10-T (idiot) form".
In the United States Air Force, a new Airman will be asked to stand in front of an aircraft and move back and forth in order to calibrate the weather radar before takeoff. Another request for new aviators is to assist in an air quality check, where they are required to run around the cabin of an aircraft with a plastic trash bag and fill it with air before tying it off and writing the name of the Air quality project on it “I-D-10-T”. This would then be proudly presented to maintenance personnel upon landing.
In Boy Scouts, sending a new camper over to other campsites to borrow a "left handed smoke bender (or shifter)",or a “sky-hook”.  "elbow grease", or "100 feet of shoreline" are similar practices.