My partner and I are video game fanatics; they are more into this video game franchise than I am (a matter of taste and nostalgia) and they have been bringing in new plants without planning where to put these (average plant lover behavior), causing us to have to improvise with too many generic pots.

The generic pots we end up finding to meet the demand (we've had to give up plants), end up being a bit boring, similar colors and shapes, and in quantity they don't end up looking that great in the spaces of the house, not to mention that they are plastic and several have deteriorated over time, especially the outdoor plant pots.

Looking at Kirby items to buy for my significant other I came across several Mario ones and there I thought, why not make a concrete planter like the warp pipes on Super Mario, but determining how to make it, I came to the conclusion that since I have expanded polystyrene foam at home, and it is a useful material for concrete projects, I opted for a planter from the question block, since its design is square and it is more manageable for the expanded polystyrene foam (EPS) sheet a design like that.

Supplies

To make the mold:

Paper
Ruler
Marker and fine pencil
Expanded polystyrene (EPS) with 1 cm and 3 cm thick.
Cutters
Transparent silicone

To prepare the mold:

Duct Tape
Mineral baby oil
Plastic cup or container (Will serve as internal base)
Straw or plastic tube about 3.5 cm long, 1 cm wide

To make the concrete mix:

Cement
Water
Construction sand
Trowel
Plastic bucket
Protective equipment (Dust mask, gloves and goggles)

For final finish:

Sandpaper (In case of imperfections. Remember to use a mask to protect your face from dust particles).
Paint (Black, Red and Yellow)
Paint brushes
Paint sealer (I used a glossy transparent one)

Step 1: Transfer Design to Paper

Note 1: To transfer the image to the EPS foam, I thought to do it manually, measuring and marking in the foam the grid I need; until checking if someone else had not published a concrete planter like this, I found the instructable: https://www.instructables.com/DIY-Cardboard-Super-Mario-World-Question-Mark-Bloc/

And seeing what the user did with the checkered paper in Step 1, I took their idea to transfer the image to EPS foam before cutting and that way it is faster and with less risk of damage, that if an error occurs, it is erased and solved on paper and not on EPS foam. So thanks to Cyndal for their instructable and the idea of using a grid.

Note 2: I am going to leave a .pdf and an .ai with the image already made (in grayscale. In step 10, it is in color) to make the cuts for those who have the possibility to print it and/or edit it.

Note 3: Take at least 2 papers with the cut design.

- In this step you define the size you want the pot to be and which will be relevant to your design; for example, the pixelated design of the Question block of Super Mario, has a grid of 16 squares. So if I want a 16 cm pot, each square in the grid must be equal to 1 cm. If I wanted a pot of 11.2 cm, each square would be 0.7 cm. With these formulas you can make the calculation you need:

X: Size in centimeters of the pot or grid.

16: Squares of the pixel grid.

Y: Size in centimeters of each square of the grid.

Formulas:

If you have in mind the size of a grid square and want to know what size to make the pixel pot or grid:

X = 16 * Y

If you have a defined pot size and you want to know what size each grid square will be

Y = X/16

- Once you have the size of the pot/grid pixel and the size of the grid box, make:

- A box with the measure of the pot/grid.

- Then, an internal grid of horizontal and vertical lines, at a distance of the square measure between them.

For example: My square is 16 cm, because I want a pot of 16 cm, so each square will be 1 cm, so my horizontal lines must be parallel to each other at a distance of 1 cm, the same for the internal vertical lines.

- Make the design on the grid:

- First make a 16 cm x 16 cm square.

- Then make 15 inner vertical parallel lines at 1 cm distance between them.

- Do the same with 15 internal parallel horizontal lines at 1 cm distance between them.

- This resulting grid should be inside the 16 cm x 16 cm square, as shown in the images.

Then take into consideration the location of the squares of the grid with the squares of the question mark image, the 4 internal squares and transfer them to paper. This design, extract the question mark with a cutter and the 4 squares, as it will be used as a template.

Step 2: Define Preliminary Cuts in Styrofoam

As shown in the picture, make:

- Side A: Cut six (6) expanded polystyrene (EPS) rectangles 22 cm x 17 cm (with 1 cm thick EPS).

- Side B: Cut six (6) expanded polystyrene (EPS) rectangles 18 cm x 17 cm (with 1 cm thick EPS).

- Side C: Cut one (1) expanded polystyrene (EPS) square of 22 cm x 22 cm (I used 3 cm thick as this is the bottom part that will receive all the weight).

Step 3: Cutting Styrofoam

Having all the squares cut from the previous step:

- Take one (1) of the rectangles from Side A and one from Side B, and center the question mark design from Step 1, joining it at the bottom, leaving 1 cm extra above the rectangles. Mark the question mark and the squares on the inside corners (the marked squares will not be cut, it is for later gluing 1 cm cube pieces on them).

- Cut the question mark with a cutter, carefully.

- Take one (1) of the other rectangles from Side A and one from Side B and cut two frames.

From the rectangle on Side B, cut a 16 cm x 16 cm outer frame, 14 cm x 14 cm inner frame, i.e. a 16 cm x 16 cm frame, with a thickness of 1 cm.
From the rectangle on Side A, cut a rectangular frame of 18 cm x 16 cm, with a thickness of the sides of 2 cm, and the thickness of the upper and lower frame of 1 cm, resulting in an internal frame of 14 cm x 14 cm.

- With the remainder of these frames, make sixteen (16) squares of 1 cm cubed.

Tip: Use a wooden board over the cutting line to stabilize the cutter blade and make a sharp cut.

Step 4: Assemble the Cut Parts

Note: When making the mold, the face of the question mark should reverse, as if it were reflected in a mirror, so that when it is disassembled it will be right-side up.

Using the glue, assemble the respective layers of each side (A, B and C).

- Each Face A and B, duplicate to represent the lateral sides of the pot cube; these sides A and B, in turn, each have three (3) layers as done in the previous step.

- Glue Layer 3 to Layer 2, and Layer 2 to Layer 1.

- On Layer 2 of both Side A and Side B, glue the 4 cubes of 1 cm. In total there are four (4) layers 2: two (2) of Side A and two (2) of Side B, and each side requires 4 cubes of 1 cm, therefore they are the sixteen (16) cubes of 1 cm cut in the previous step.

Step 5: Assemble the Mold

- Using duct tape and regular tape, join Sides A, B and C to make a cube without a lid.

- Side C goes underneath sides A and B.

Step 6: Prepare the Mold

Glue one end of the tube (3.5 cm long and 1 cm wide) to the bottom of the cylindrical container with the silicone, and glue the other end to the center of the C side.

Tip: You can oil the walls of the mold to make it easier to disassemble the pot.

Step 7: Making Cement Mix

The ratio of sand to cement that I used is: 2 parts sand to 1 part cement, and about 1 part water (this is relative to the mixture because even the temperature of the environment influences, and what the mixture will be used for).

- Mix 2 parts sand (I used 4 kg of sand for this mold), with 1 part cement (2 kilos of cement) and about 1 part water (pour it in little by little, while mixing, and stop often to see the consistency).

- The consistency should be like creamy ice cream, or something like that.

In image 1, the mixture is too watery for this mold, as the water can run off.

In image 2, it is the consistency you are looking for this mold.

Step 8: Pour Cement Into the Mold

- Pour the mixture prepared in the previous step into the mold.

- Vibrate the mold carefully to eliminate the possibility of bubbles.

- Depending on the color of the result you want in the cement, I would recommend varying the sand used. The one I used is dark, gravel type.

Tip: Cover with a plastic bag to allow moisture to remain in the cement as this helps the cement to cure.

Step 9: Dismount

- In 24 hours the pot can be disassembled; 3 to 5 days it can be used, but keep in mind that the complete curing of the cement takes about 28 days.

- In this step, sandpaper can be used to remove any imperfections in the pot before painting. Wear gloves, goggles and a safety mask because this dust can cause respiratory problems.

Tip: Curing can be accelerated by constantly hydrating the cement pot. Some people after 24 hours and demolding, immerse the cement object in water and leave it for 1 week.

Step 10: Paint Flower Pot

The pot has 3 colors. Black and two different shades of orange. For these two orange tones, you have to use these parts of paint approximately until you find the color:

For me it worked relatively well with these measurements:

- Orange 1 (#F8983C): Three parts yellow, one and one-half parts red.

- Orange 2 (#C84E27): Three and a half parts red, 2 parts yellow, a small pinch of black (ultramarine blue can be used instead).

After finding satisfactory shades of orange, you can use the painting guide.

After painting, use clear fixative to set the color (use a mask because the odor is strong, and preferably use the sealer in a ventilated area.)

Question Block - Colour Pattern.ai
Download

Step 11: Final Aspects

I recommend using EVA foam or some similar material, instead of EPS, because EPS is more messy to use and not very reusable cast. Although there are ways to recycle EPS after use.