A cross-section of the box, 16 by 20 cm. Roots follow the water through the holes, thicken and split the stone. The stone falls and breaks capsules, and the seeds that survive start another generation. Each cell is a millimetre and each step is a week.
It uses the values from two research reports, one on stone and plant and one on sealed seed: the strength of each stone once wet, the pressure a root can hold for years, and the life of a dry, sealed seed, following the Ellis and Roberts curve. How fast the root thickens and how long the seed really lasts are still assumptions until the physical test measures them. Since version 3.3 you can choose natural London light through the seasons, and rules that break ampoules from outside. Version 3.4 adds the urn: anyone pays to break an ampoule and chooses in secret whether the box lives or dies; the price doubles with each purchase. In 3.5, the urn pays the rent for its place with what it raises, and if the money runs out, the box is removed. In 3.6, each type of ampoule has its own stock: 30 of seeds and 20 of salt give a tie. In 3.7, the ampoules come from the operations in the compendium: besides seeds, salt and water, you can break extra water, desiccant, ink, resin, hormone, compost or acid. Use it to compare designs. It can't predict dates.
Nobody else will see what you choose until the urn opens. All the ampoules look the same.
Running.
Each dot is a purchase. The grey dotted lines are the openings: a grey dot takes its shape when the urn opens: ● seeds, ■ salt, ○ water, ◆ resin, ▲ hormone, ▮ ink, ◎ extra water, □ desiccant, ✚ compost, ✕ acid. The green dotted line is the fund that pays the rent.
Changing a setting restarts the box with the same stone. "Another box" changes the stone, its veins and the random draw.
Before, root strength was a free multiplier. Now each hole in the section stands for a line of holes that runs 15 cm into the box. The root thickens until it fills each hole and pushes with a pressure of about 0.3 MPa. The stone bridges between holes break if that pressure is greater than their wet strength. The root thickens most near the trunk, so each plant only splits the slab beneath it. Dry, sealed seed follows the Ellis and Roberts curve: it barely loses strength for years and then drops fast, sooner in the heat. The fig only germinates in light; in shade it stays dormant. Each bar sums up 40 boxes over 40 years.
With the fig and Robinia mix, seed at its central values, 21 °C and roots that thicken 1 mm a year. LED light and no outside rules.
Bath limestone with grooves, 21 °C except where stated. Half-life of dry, sealed fig seed at 20 °C: 2, 8 and 30 years are the low, central and high values in the seed report. The first row is version 3, with the old curve and no light. LED light and no outside rules.
In version 2, with root strength as an assumption, putting the capsules on the slab that will fall raised the boxes reaching the third generation from 30% to 62%. That idea still holds: it is the basis of the two new layouts.
This version adds two things that come from outside the box. The first is natural London light: the box starts on 1 April and in December gets about a tenth of the light it gets in June. The second is rules: a shelf under the lid with 15 ampoules per rule, which break when something happens outside, for example every £1,000 of donations. Each ampoule holds seeds, nutrients, weak acid or salt. In the simulation, each rule breaks the number of ampoules a year you set, on average, in random weeks. Each bar sums up 80 boxes over 40 years.
Redesigned floors, Bath limestone with grooves, 3 mm holes, Robinia mix and 21 °C. The default rules break seeds, acid and nutrients, one ampoule of each type every two years. The outlined row marks the settings the page opens with. Since version 3.4 salt drains into the water and stays there; the salt rows were recalculated with that.
For the piece: loose acid or nutrients don't change the story of the box, because the box absorbs them. Salt does, because it builds up: in a closed box nothing takes it out.
Anyone can pay to break an ampoule and choose in secret between seeds, so it lives; salt, so it dies; or water, which does nothing. Who paid and how much is public; what they chose is known when the urn opens, every 5 years. The price starts at £20, doubles with each purchase and halves after a year with no purchases. There are 30 ampoules of seeds, 20 of salt and 20 of water. Salt drains into the water and stays there, because the box is closed. Since version 3.5, everything paid goes into a fund that pays the rent for the space; if the fund runs out, the box is removed. I ran 40 boxes over 40 years per row with an invented public: 40 people a week think about it, a typical person would pay £4 and a few much more; 45% want it to live, 35% want it to die and the rest pay for the gesture.
Redesigned floors, Bath limestone with grooves, 3 mm holes, Robinia mix, 21 °C, LED light, 0.13 g of salt per ampoule, and 30 ampoules of seeds, 20 of salt and 20 of water, except where stated. Rows with rent start with a fund of £1,200. Life: years with something alive and in place, median. Plants: how many lived in total, median. Raised: what the public paid, median.
20 salt ampoules of 0.13 g, 20 of water and no rent. Majority: 60% against 20%. Split in two: 40% against 40%. 40 boxes over 40 years per point.
For the piece: rent turns money into time. Each purchase pays for months in the room, whoever makes it. What you decide before sealing the box is how much salt each ampoule holds, how many seeds are on the rail, how much the space costs and how big a fund it starts with.
Each ampoule is an operation from the compendium brought into the box. Seeds are Seed And Leave, salt is Ratchet and plain water is Rehearse: the whole gesture, with no consequence. Since version 3.7 there are seven more. To see what each one does on its own, I ran 40 boxes over 40 years with 15 ampoules of that type, one a year, with no urn and nothing else from outside.
| Ampoule | What it does in the box | life | plants | 1st slab | lines |
|---|
Redesigned floors, Bath limestone with grooves, 3 mm holes, Robinia mix, 21 °C and LED light. Life: years with something alive. Plants: how many lived in total. 1st slab: the year the first one falls. Lines: how many lines of holes split. Medians of 40 boxes. Without a lasting source of seeds, every box goes out before 40 years; what changes is when and how.
The rules of the urn are operations too: the rising price is Raise The Cost, the secret choice is Conceal, the urn sealed until its date is Delay, the rent is Lease, the seed mix is Hedge and the box itself is Weather.
The two things nobody has measured are how fast the root thickens and how long sealed fig seed lasts. Each square sums up 48 boxes over 40 years with that combination, in redesigned floors, Bath limestone with grooves and 3 mm holes. The number is the percentage of boxes that reach the third generation. The dotted outline is the likely zone according to the reports, and the ring is the central estimate. The fig only germinates in light. LED light and no outside rules.
Run many boxes with the settings above, changing only one. Each bar shows which generation the boxes with that value reached. The edge is where the bars suddenly change colour: there, a small change in the design decides whether the cycle goes out early or links several generations.
Above each bar, the average generation. Below, the value tested and how long a typical box lasted before going out.