Here is a river crossing puzzle (note that whenever I use the term "colors", I mean the squares):
Yellow and Red are on one side of the river, while Pink, Blue, Green and Black are on the other side.
There is a singe boat that can hold at most 2 colors on the side where there are four colors.
Some of the colors have bonds and/or beefs with other colors.
Here are all the color's requirements:
Yellow won't go with Black
Red will only go alone
Pink will only go if Yellow is going
Blue won't go with Green, and will only go if Yellow is going
Green will go without any conditions
Black won't go alone and won't go with any of Yellow and Blue.
Here is an example where I bring the colors across in a total of 9 trips:
Find a way to bring all the colors to the opposite sides of the river in under 9 boat trips.
I programmed the tool in the above example. You can find the tool here.