A simple bee feeder that fits as a lid on an Archer Farms jar of nuts you can get from Target. The jar is large and wide, but still short enough to fit inside a standard size super. Fill the jar with syrup or water, screw on the lid, place the jar with the lid down into your hive, and unscrew until liquid starts to come out through the holes. The doughnut shaped rim is high enough to be over the square holes, so when the trench fills, no more liquid should escape from the jar. And being round and fairly flat, it will make it easy for bees to climb over, while staying shallow enough for them not to accidentally drown. With the trench all around the jar there's plenty of room for everyone to drink. Just make sure to print with PLA or other non-toxic materials.
The side of the lid is pretty large, and might not fit on smaller printers, but it should be possible to modify the file to make the rim a bit smaller.
Using PLA or other non-toxic filament