The mathomancer’s toolbox is a collection of magical items that can be used to alter blasting spells in your 5e games. Its targeted towards your math nerds, but anyone who likes breaking out a ruler in your game and measuring exact distances will like them. If determining the exact best placement for your spells is the worst part of the game, go ahead and read another article. We have tons, and won’t be offended.

Transangular Protractor (Very Rare)
This magical measuring device can be wielded in place of a wand, staff, orb, or other arcane implement. When used to cast a spells that target a cone, cube, cylinder, line or sphere, the spell can be modified based on the number of charges spent. It has 10 charges, resetting on a long rest.
- 1 Charge – Sculpt Spell – Your spell can change to another traditional areas. a 15ft cone, a cube with 20ft sides, a 10ft radius cylinder 50ft high, a 100 ft line, or a sphere with a 15ft radius.
- 3 Charges – Imaginative Sculpting – Your areas can be non-traditional shapes for spells. A rectangular prism with sides 10ft and 40ft across, a curved wall up to 75 ft long (singular curve, but you can determine the acuteness), a hollow dome with a 15ft radius, or a torus with a 20ft radius.
- 6 Charges – Non-Euclidian Geometry – You can come up with some really wild shapes. They don’t even have to be contiguous on the third dimension. You can divide the normal area of the spell up into 5ft cubes, and place them as desired, provided none of them are further than you could normally cast the spell.
Geometer’s Slide Rule (Very Rare)
This device can be held and used to channel arcane magic. It has 10 charges that renew after a long rest. Whenever you cast a spell with the area of effect, Line you can expend a charge to alter its properties.
- 1 charge – Extend – You can exclude the first 10ft of distance from the effects of your line spell. You can spend multiple charges to exclude an additional 10ft per charge.
- 1 Charge – Shorten – You can exclude the last 10ft of distance from the effects of your line spell. You can spend multiple charges to exclude an additional 10ft per charge.
- 2 Charges – You can originate your line from a square 10ft in front of you. You can spend multiple charges to exclude an additional 10ft per 2 chargees.
Compass of Dilation (Very Rare)
When used to as the focus of a spell, the compass of dilation allows spheres and spells that emanate from the caster to increase or decrease their range. It has 10 charges that renew after a long rest.
- 1 Charge – Reduce the radius of a spell by 5ft. You can expend multiple charges to reduce an additional 5ft.
- 1 Charge – Exclude a creature within the radius of the spell from its effects for one round.
- 2 Charges – Increase the radius of the spell by 5ft. You can expend multiple charges to expand an additional 5ft.

Focused Prism (very rare)
When spells are cast through the focused prism, the effects can split into multiple zones. It has 10 charges which renew after a long rest.
- 1 Charge – Split Cone – The spells cone width is divided in half. You can cast the spell twice, each one dealing half the normal damage it would. You can continue to half the damage (down to 1 die of damage) and divide the cones by spending more charges.
- 1 Charges – Slight Adjustment – You can change the elemental type of any damage dealt to any other type. If you are splitting your cone, you must pay per split you want adjusted. Each new cone can be a different elemental type if you desire.