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.

Marceline

Colours;
White
Mauve/Light Purple
Red
Grey
Black

Using black , chain 51.
Row 1: Work 1dc in 4th ch from hook, then work 16black, 4red, 9mauve, 18black.
(48dc’s + 3 starting ch = 49dc’s).
Row 2: Work 18black, 9mauve, 4red, 18black.
Rows 3 & 4: Work 18black, 13mauve, 18black.
Row 5: Work 18black, 4red, 9mauve, 18black.
Row 6: Work 18black, 9mauve, 4red, 18black.
Rows 7 & 8: Work 15black, 19mauve, 15black.
Rows 9 & 10: Work 12black, 6mauve, 3white, 7mauve, 3white, 6mauve, 12black.
Rows 11 & 12: Work 9black, 9mauve, 13black, 9mauve, 9black.
Rows 13 & 14: Work 6black, 9mauve, 4black, 11mauve, 4black, 9mauve, 6black.
Rows 15 -18: Work 6black, 37mauve, 6black.
Rows 19 & 20: Work 6black, 9mauve, 4black, 11mauve, 4black, 9mauve, 6black.
Rows 21 & 22: Work 6black, 37mauve, 6black.
Row 23: Work 9black, 6mauve, 4black, 21mauve, 9black.
Row 24: Work 9black, 21mauve, 4black, 6mauve, 9black.
Row 25: Work 12black, 6mauve, 4black, 15mauve, 12black.
Row 26: Work 12black, 15mauve, 4black, 6mauve, 12black.
Row 27: Work 15black, 6mauve, 4black, 9mauve, 9black, 3grey, 3black.
Row 28: Work 3black, 3grey, 9black, 9mauve, 4black, 6mauve, 15black.
Row 29: Work 18black, 3mauve, 4black, 6mauve, 9black, 3grey, 6black.
Row 30: Work 6black, 3grey, 9black, 6mauve, 4black, 3mauve, 18black.
Row 31: Work 37black, 3grey, 9black.
Row 32: Work 9black, 3grey, 37black.
Finish off, sew in ends.