I searched ‘Adventure Time’ graphs on Google and Pinterest for ideas, then made up my own graphs to work with. They are 16x16 square graphs. I worked 2 rows of (US) double crochet per 1 row of squares on the graph to get it close to square. Half-double crochet would also be suitable to use for these graphs.
My squares turned out ever so slightly rectangle (at 31cm x 33cm approx. 12” x 13”- had I worked in hdc, they would have been square)….but that’s fine for what I’m using them for.

Solid granny squares could also be used as an alternative here - 1 square on the graph = 1 granny square. You can make them whatever size that you like.

Graphs may also be worked in C2C (corner-to-corner) method. Here are two tutorials to help with C2C and how to colour change;
https://www.youtube.com/watch?v=qq_5lflBMIg
https://www.youtube.com/watch?v=3mBI7_uTWPc

I started each row with a chainless starting dc - it produces a more even edge, but you can also begin your rows with the standard ch3 if you wish.
Here’s a link to a Moogly ‘how-to’;
http://www.mooglyblog.com/chainless-starting-double-crochet/
If you need help with how to colour change, go to YouTube and look up ‘Intarsia Crochet’ tutorials…there are a few to choose from there.

I have added pics of the charts that I made - they include a little group of colours at the bottom of the pic. Use those to help you match your yarn choices.

When working the odd numbered rows (1, 3, 5, etc)…the side facing you will be the right side of your work. Looking at the graph, your rows will be worked odd numbered rows from the R-L and the even rows copy what you did in the previous row - ie: Work Row 1, Row 2 will be the same as Row 1 but the order will be reversed. A tip - each stitch worked in the even rows will be the same as the stitch below it in the previous odd numbered row.

Beemo

Colours;
Blue Green (b/g)
Light Mint Green (mg)
Olive Green
Lime Green
Red
Royal Blue
Light Blue
Yellow
Black

Using your main colour - a green/blue (referred to as b/g from here on), chain 51.
Row 1: Work 1dc in 4th ch from hook, then work another 7dc’s in the b/g, work 13dc’s in red, 6b/g, 6royal blue and 15b/g. (48dc’s + 3 starting ch = 49dc’s).
Row 2: Work 15b/g, 6 royal blue, 6b/g, 13red and 9b/g.
Row 3: Work 12b/g, 7red, 18b/g, 3yellow, 9b/g.
Row 4: Work 9b/g, 3yellow, 18b/g, 7red, 12b/g.
Row 5: Work 6b/g, 3lime green, 25b/g, 9yellow, 6b/g.
Row 6: Work 6b/g, 9yellow, 25b/g, 3lime green, 6b/g.
Row 7: Work 15b/g, 10light blue, 12b/g, 3yellow, 9b/g.
Row 8: Work 9b/g, 3yellow, 12b/g, 10light blue, 15b/g.
Row 9: Work 18b/g, 4light blue, 27b/g.
Row 10: Work 27b/g, 4light blue, 18b/g.
Row 11: Work 9b/g, 4royal blue, 15b/g, 15olive green, 6b/g.
Row 12: Work 6b/g, 15olive green, 15b/g, 4royal blue, 9b/g.
Rows 13 & 14: Work 49b/g.
Rows 15 & 16: Work 9b/g, 31light mint green(mg), 9b/g.
Rows 17 & 18: Work 6b/g, 15mg, 7black, 15mg, 6b/g.
Rows 19 & 20: Work 6b/g, 12mg, 4black, 5mg, 4black, 12mg, 6b/g.
Rows 21 & 22: Work 6b/g, 37mg, 6b/g.
Rows 23 & 24: Work 6b/g, 6mg, 4black, 17mg, 4black, 6mg, 6b/g.
Rows 25 & 26: Work 6b/g, 37mg, 6b/g.
Rows 27 & 28: Work 9b/g, 31mg, 9b/g.
Rows 29-32 : Work 49b/g.
Finish off, sew in ends.