Arched Lid Box

The key to this curve is a concept called the sagitta — the height of an arc above its chord. Using this, you’re not locked into a fixed semicircle; you can choose exactly how gentle or deep the curve is. For this box, we went with a subtle, shallow arc: R=80mm with a rise of just 17.6mm.

Rounded Corner Tray

ITOSHIGE STUDIO has made many kinds of trays over the years. This time, we wanted to round the corners.
We’ve always made 90° corners before — rounding just this one part turned out to be far more involved than expected. There’s more than one way to do it, and here we’re introducing one method we use.

Basic Tray -Sandwich

Don’t throw away your scrap cardboard — turn it into something useful and beautiful.In this video, I’ll show you how to make clean, elegant trays using the sandwich technique — working with three different cardboard thicknesses: 3.5 mm, 4 mm, and 6.5 mm double wall.

Laptop Stand

Built entirely from 7mm thick corrugated cardboard, this project is packed with techniques: seamless edge finish, interlocking Paper Hinge, stopper, angled cut, internal shelf, cable hole, and magnetic closure.

3-Way Pen Stand

I designed a new pen stand — but instead of just gluing
boxes together, I rethought the structure from scratch.

The result? A 3-way pen stand that works upright,
flat on its side, or leaning against a wall.

The build is a little more involved, but if you have
cardboard sitting around at home, why not turn it into
something useful for your desk?

Fillet Catchall Tray

Build a minimal catchall tray from corrugated cardboard — no complex joinery, just 3 pieces and a technique you haven’t seen before. The inner edges are shaped into a smooth Fillet, making it easy to slide out pens, keys, or anything you drop in. Upcycled from Samsung TV packaging.

Picture Frame 3.0

Building on previous versions, this design introduces a sloped inner frame, creating a more refined and architectural look. The structure is significantly more complex than before, but the result is strong, clean, and visually elegant — while staying true to sustainable principles.
This project explores how far cardboard can go when we fully understand its structure and use it intentionally.

Lampshade

A modern cube-style lampshade using L-shaped frame pieces. Designed for ambient lighting, this lightweight and stylish piece is perfect for home decor projects using sustainable materials.
*For this project, I used a Baby Night Lamp (LED).
Cardboard is a flammable material, so using incandescent bulbs or other heat-generating lights can be dangerous. Please make sure to use a low-heat LED light only.