I made this cake for a pair of high school graduates who were both on the school's water polo team. They requested a water polo cake.
To start with, I made a simple 2-layer 12x18 white cake with a strawberry flavored buttercream filling. Then I cut out the middle of the top tier about 2/3 the way down the cake. After crumb-coating, I covered just the sides with fondant. I first planned to roll out a single, large sheet of fondant and cover the whole cake with that single piece. It would have looked a lot nicer without all of the seams. But I couldn't see wasting all that fondant. It's not like I'm running a for-profit business here. So, instead, I rolled out some wide strips and wrapped them around the side of the cake. You can see some seams, but I was tired and in a mood to say "good enough". Nobody complained. :-)
The water was just blue icing. I used a flat tip and piped it into the pool. Then I used a small, warm spatula to smooth it out. It wasn't perfectly smooth, but that's okay.
To make the goals, I used a stiff royal icing mix along with number 5 and number 3 tips. The number 5 tip was used to pipe the borders and the number 3 tip to pipe the netting. I used a computer program and made appropriate sized boxes, printing them on to paper. With a piece of waxed paper over the computer paper, I piped the pieces for the goals. I only needed two goals, but piped royal icing is VERY fragile. I didn't have time to repipe in case of breakage. So, being proactive, I just made four goals instead of two. After a day and a half of drying time, I peeled them off of the wax paper. Fortunately, there were no breaks. Yay! Extra royal icing candy! At the back of a water polo goal is a fabric/tarp sort of thing that the ball hits. I don't know what it's called. I'm sure a water polo guru could tell us. I'll call it a backstop, I guess. Anyway, those are easy to make. Color up some gum paste, roll it nice and flat (and thin) and then cut to size.
Goal assembly was simple. Place the back into the water icing. Then the two sides. Then the blue backstop. Pipe a thin line of royal icing along the tops and place the top netting piece on. I piped royal icing along any gaps to fill them in and give some stability. It dries quickly enough and they were glued well.
To sculpt the players, I used gum paste and pieces of dry spaghetti. The dry spaghetti worked better than toothpicks because they are edible. They are also a touch thinner and easier to break into smaller pieces. To color the players, I used a touch of "creamy peach" and then "ivory" paste colors from Wilton. I ran out of colored gum paste and had to color a second batch. The colors didn't match up exactly, so I just made sure to not mix the two colors on any one player. Most of the players are just heads with necks since they are all in water. Deep water. I made a few with torsos and just two with arms of any kind. I wasn't going for any kind of realistic detail opting, instead, for a cartoony feel. I drew their faces using edible food color markers. Their hats were just rolled out pieces of gum paste with little dots of gum paste for the ear guards. In reality, their hats cover more of their face as there are chin straps on them. I was too tired for that kind of detail, so I called it "artistic interpretation". You can get away with so much with that excuse. :-) The numbers on the white hats were drawn using the same food color markers as the faces. Obviously, I have a multi-color pack. The recipient of the cake provided me with a list of numbers I could use for the players. For the numbers on the brown hats, I couldn't use the markers. I don't have any white ones. So I put a number 1 tip into a parchment bag and thinned out the royal icing a bit.
Final assembly involved placing the players into the water in a way as to make it look like the white hat players (the graduate's team, after all) were beating up on the brown hat players. I lightened some of the blue icing a bit and piped it with a number 2 tip around the active players in the water for a splash effect. I determined that players with more than just their head out of the water were the "active" players that got the splash effect.
I wasn't able to attend the graduation party, but I got some feedback the following day. Without realizing it, I chose the hat colors of one of the team's rivals. And the number 27 the other team's goal keeper belongs to a member of that other team that most of the players and parents on the local team knew. None of that was planned, but graduates on the team really enjoyed the scene of them beating up on one of their rivals like that. They wondered how the cake guy knew about that other team. I didn't, of course. I just felt like using brown hats and the number 27.