Bonsai Banks

Tradeable Savings Accounts featuring evolving digital artwork and game-mechanisms to incentivize saving.

Overview

• Bonsai Banks are bonsai NFT artworks that must be tended to using on-chain transactions
• Each Bonsai Bank...
  • is minted by the botanist or contract owner
  • must be watered by depositing 20 DAI into the bank every 7 days
  • must be fertilized by depositing 0.02 ETH into the bank every 30 days
  • can wilt if watering is more than 7 days late and 5% of the deposits will go to the botanist
  • can grow if taken care of correctly for 90 days the botanist will make an enhancement to the bonsai art
  • must be destroyed to recover the deposits plus an interest earned

Protocol Specification

Parameters

• address botanist - The owner of the contract and the producer of the artworks
• BonsaiBank[] bonsaiBanks - A list of all the bonsai banks indexable using bonsaiIds
• address waterToken - The token used to water the plant
• address fertToken - The token used to fertilize a plant
• uint256 waterAmount - The amount of waterToken needed to water the plant
• uint256 fertAmount - The amount of fertToken needed to fertilize the plant
• uint256 waterRate - The duration in seconds to wait between waterings
• uint256 fertRate - The duration in seconds to wait between fertilizings

Structures

• BonsaiBank
  • uint256 lastWatered - The unix timestamp when the plant was last watered
  • uint256 consecutiveWaterings - The number of consecutive waterings
  • uint256 lastFertilized - The unix timestamp when the plant was last fertilized
  • uint256 consecutiveFertilizings - The number of consecutive fertilizings
  • uint265 bonsaiId - The id of this BonsaiBank, used as the token ID for NFTs
  • string[] bonsaiUris - A list of all the images in cronological order for this BonsaiBank
  • int lifeStage - An index into bonsaiUris and references the plants current image URI
  • mapping(address => uint265) balances - A mapping of token addresses to amounts deposited to the Bonsai bank

Modifiers

• onlybotanist - modifies methods so they can only be called by botanist

Methods

mint(address caretaker, string bonsaiURI)

• Parameters
  • caretaker - The address this bonsai is minted to
  • bonsaiURI - the URI associated with the minted bonsai
• Pre-conditions
  • None
• Post-conditions
  • 1 BNZI is transferred to caretaker

water(uint256 bonsaiId)

• Parameters
  • bonsaiId - The id of the bonsai to water
• Pre-conditions
  • Must approve waterAmount amount of waterToken
• Post-conditions
  • Transfer waterAmount amount of waterToken to the BonsaiBank
  • Resets lastWatered timestamp
  • Increments consecutiveFertilizings
  • balances is increased to reflect the deposit

fertilize(uint256 bonsaiId)

• Parameters
  • bonsaiId - The id of the bonsai to fertilize
• Pre-conditions
  • Must approve fertAmount amount of fertToken
• Post-conditions
  • Transfer fertAmount amount of fertToken to the BonsaiBank
  • Resets lastFertilized timestamp
  • Increments consecutiveFertilizings
  • balances is increased to reflect the deposit

grow(uint256 bonsaiId, string bonsaiUri) onlybotanist

• Parameters
  • bonsaiId - The id of the bonsai to water
  • bonsaiUri - The id of the new image for the plant
• Pre-conditions
  • The bonsai has 12 consecutive waterings and 3 consecutive fertilizing
• Post-conditions
  • The new bonsaiURI is added to the bonsaiUris
  • The lifeStage is incremented by 1
  • consecutiveWaterings and consecutiveFertilizings are reset

wilt(uint256 bonsaiId) onlybotanist

• Parameters
  • bonsaiId - The id of the bonsai to wilt
  • bonsaiUri - The id of the new image for the plant
• Pre-conditions
  • It has been waterRate * 2 seconds since the last watering
• Post-conditions
  • 5% of all balances for this bonsai are slashed and set to the botanist
  • consecutiveWaterings and consecutiveFertilizings are reset

destroy(uint256 bonsaiId)

• Parameters
  • bonsaiId - The id of the bonsai to destroy
• Pre-conditions
  • The message sender is the holder of the bonsai
• Post-conditions
  • The NFT is burned and all balances are sent to the message sender