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.

Peppermint

Colours;
White
Red
Royal Blue
Black

Using your royal blue, chain 51.
Row 1: Work 1dc in 4th ch from hook, then work 7royal blue, 4black, 6red, 3white, 5black, 3white, 6red, 4black, 9royal blue. (48dc’s + 3 starting ch = 49dc’s).
Row 2: Work 9royal blue, 4black, 6red, 3white, 5black, 3white, 6red, 4black, 9royal blue.
Rows 3-8: Work 9royal blue, 31red, 9royal blue.
Rows 9 & 10: Work 15white, 4red, 11white, 4red, 15white.
Rows 11 & 12:Work 49white.
Rows 13 & 14: Work 3red, 43white, 3red.
Rows 15 & 16: Work 6red, 12white, 13black, 12white, 6red.
Rows 17 & 18: Work 9red, 6white, 4black, 11white, 4black, 6white, 9red.
Rows 19 & 20: Work 12red, 25white, 12red.
Rows 21 & 22: Work 49white.
Row 23 & 24: Work 12white, 4black, 17white, 4black, 12white.
Rows 25 & 26: Work 21white, 7red, 21white.
Rows 27 & 28: Work 9red, 9white, 13red, 9white, 9red.
Rows 29 & 30: Work 6red, 9white, 19red, 9white, 6red.
Rows 31 & 32: Work 3red, 9white, 25red, 9white, 3red.
Finish off, sew in ends.