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Everything it does

Seven groups, 56 things the shipped product does today, each named with the lane that built it. 5 of the 14 feature loops play on the front page; the rest play here. Nothing on this page is planned — if it is here, it is in the app.

01

Write the mathematics

Natural notation in a live field, evaluated top to bottom by a symbolic engine with the units carried through every operation.

Natural notation
Type ≔ and the field becomes a definition. Fractions, roots, subscripts and Greek as you would write them; = evaluates in place.
CC-P2c
Units are load-bearing
Every value is a quantity. Adding a moment to a length is a typed refusal, never a silent number. Preferred display units per dimension; custom units per workspace.
CC-P3a
A library of 208 functions
Trigonometry to special functions and distributions; matrices, ranges, Σ and Π; and your own f(x) ≔ beside them.
CC-F3
Show your working
The substitution line prints under the result, so a checker sees the numbers that went in without opening anything.
CC-C4
Formulas that break across lines
A long formula wraps at its own seams, on screen and on paper, and edits in place without the page shifting.
CC-L51
Symbolic →
Simplify, expand, factor, differentiate and integrate in the same field, symbolically.
CC-P7
Predefined constants
g_n, N_A, k_B and their kin, exact by definition, shadowable with a warning rather than an error.
CC-C42

Show your working

The substitution line prints under the result, so a checker sees the numbers that went in without opening anything.

LOOP-02

Animation off — showing the result.

02

Change one thing

A sheet is a calculator the moment an input moves. Everything downstream re-inks, nothing goes stale in silence, and the logic is written where it can be read.

Inputs and controls
Sliders, dropdowns, toggles and steppers bound to definitions, on the sheet and in a table column.
CC-C7
Solve blocks
Name the unknown and give the constraints. An exact route where a closed form exists, Newton otherwise, and the guess selects the root.
CC-P7
Programs
Branches and loops in a small interpreter that never runs eval. A definition with parameters is a function the sheet calls.
CC-P7
The trace
Step through a figure's program: the gutter shows each row's value, and the canvas lights the shapes that row drew.
CC-FUI1c
Zones
Scope a run of blocks: keep it off paper, show it only when a condition holds, number its sections.
CC-C6
Checks with verdicts
η ≤ 1.0 and the chip says so. Two-bound bands, a failed check that shows its value, and a rail that lists every check on the sheet.
CC-C39
Manual calculation, calc from here, a Watch panel
Hold the sheet still while you edit, recompute from a chosen region, and watch the values you care about.
CC-P7b

Programs, not nested IFs

A branch is a branch. The condition is visible in the sheet rather than buried in a formula bar.

LOOP-08

Animation off — showing the result.

Zones

Scope a set of blocks and reuse them. It answers a question a first visitor does not have yet.

LOOP-07

Animation off — showing the result.

03

Draw it

A figure is geometry bound to the sheet's variables. Coordinates are expressions with units, the picture is derived rather than stored, and it prints as vectors.

Parametric figures
Bindings flow in, measurements flow out. Change a variable and the drawing redraws; a measured length is a document symbol.
CC-PF1
A CAD hand
Typed coordinate entry, eight kinds of snap, grips on every point, trim, extend and fillet, and six modify gestures — every one producing an expression, not a literal.
CC-CAD1
Dimensions, hatches and weld marks
Linear, chain, ordinate and angular dimensions; ISO 128 hatches; ISO 2553 weld marks; the clearance stack a fall-arrest sheet draws.
CC-FIG4
The concrete section
Faces, bars and links drawn from the section's own dimensions, hatched as the discipline hatches them.
CC-FIG5
Drawn once
A definition is a routine. Place it by position, rotation and mirror; four starter profiles — CHS, RHS, UB and angle — parameterised by their dimensions.
CC-FIG6
Drafting furniture
S-breaks, a north arrow, section and detail markers, and a scale bar whose words are derived from its own two points.
CC-FIG7
Layers
A condition, a print flag, a default style and a lock per layer, so setting-out geometry can stay off paper.
CC-CAD5
DXF export
The drawing the sheet computed, as R2000 DXF, from the figure's menu and from the standalone runner.
CC-CAD6
Charts
Seven chart kinds in hand-rolled SVG, printed as vectors, with a table as a plot's input.
CC-P4d
Figure programs
A drawing loop emits geometry from a program, so a pattern of n bolts is n, not a picture of six.
CC-PF2

Parametric figures

The drawing redraws with the numbers. A section that reads at length once the figure block has been introduced.

LOOP-04

Animation off — showing the result.

04

Tabulate it

A table is a grid of expressions that carries units, publishes its columns as variables, and edits like a spreadsheet.

Tables that compute
Cell formulas, a format and a unit per column, a ✓/✗ column that checks itself, and columns that are document variables.
CC-P4a
Cell addresses and ranges
A1-style references with $ pins, ranges, a formula bar that answers, coloured references, and a corner drag.
CC-TBL13
Lookups
Bracketing and stepping lookups over a keyed column, with a typed refusal for a key off either end.
CC-F1
Data tables with global columns
A schedule declared global is readable above and below itself, per column.
CC-L46
Typed columns
Words, truth values and pasted values beside numbers, each column saying what it holds.
CC-C3
Schedules that drive instances
A batch region drives one template sheet from a schedule's rows; the cover computes over every instance, and each prints.
CC-BATCH2
The STAAD bridge
OpenSTAAD on your own Windows machine, through MCP. A landed table carries its origin stamp onto the issued page.
CC-STAAD2
Sized by the page
Column widths as fractions of the content box, wrapped and hidden columns, and print parity for all of it.
CC-TBL8b

Tables that compute

Every cell is an expression, every column carries a unit, and the utilisation column checks itself. Nine tables in this document; none of them is a picture.

LOOP-06

Animation off — showing the result.

05

Print it

The page you print is the page you wrote: one paginator, one title block and one sheet on screen, on paper and in the PDF.

The page model
A4, A3 and Letter, margins, explicit breaks, columns and section breaks, headers and footers edited on the page.
CC-C5

Issue and revision

A sheet that is issued stops moving. It matters enormously to a buyer and not at all on a first visit.

LOOP-10

Animation off — showing the result.

06

Work together

Two people, one sheet, live — and the record it becomes.

Live co-editing
Yjs-native from the first line: presence, carets, per-character merges, every result recomputed on every machine.
CC-P1d
Comments and mentions
Anchored to a region, resolved in place, with a notification for the person named.
CC-P8
Versions and a calc-aware diff
A named snapshot, restored in one step, with a diff that knows which numbers moved.
CC-P8
Share and publish
Roles, view-only links, and a published page that reads with no account.
CC-P10d
Standalone export
One file, offline, still live: the engine and the sheet in a folder that opens from the filesystem, inputs working.
CC-P10f-a
The .sheaf file
Save and open a calculation as a file; an assembly is a .sheafasm and a project a .sheafproj.
CC-C5
Offline drafts
A local replica in the browser; a reconnect merges, and the status bar says which.
CC-P9
A blank sheet with no account
The front door is a working sheet with the real engine. The account is the price of keeping the work, not of doing it.
CC-P10g-b

One file, offline, still live

Send a calculation to somebody with no account and no network. The inputs still work.

LOOP-12

Animation off — showing the result.

07

Let it write

The Assistant writes a sheet from a description, extends or fills one you are editing, and reads the house's guide before it does.

Describe it, get a sheet
Say what you are checking; the sheet arrives written, evaluated, and open for editing.
CC-P10i-a
Every block family on the first turn
Tables, figures, charts, controls, programs and solve blocks — not only mathematics — plus the paper size and the result display.
CC-AS2
The in-document panel
Ask for a change to a region. Apply is one transaction on your own sheet; the server never writes a live document.
CC-P10i-c
The outline builder
A brief per section, a saved outline that reopens as saved, and a sheet written from it in stages.
CC-P10j-a
Runs that outlive a tab
A long generation runs on a worker; reload and the sheet is still being written.
CC-P10j-k
The house style and its guide
An office's palette, paper and defaults, copied into a sheet at birth, and an authoring guide the Assistant reads on every ask.
CC-HS4
The MCP connector
Seventeen tools: validate, create, evaluate, render a PDF, edit, outlines, templates and the vocabulary — for the Claude you already use.
CC-P10e
Documentation and a function reference
Walkthrough frames shot from the shipped components, and one page answering what every function takes, returns and refuses.
CC-D5
The outline builder inside the editor
the outline beside the sheet, every region in the order it is read