@calcutts_ivy is a twitter enabled Hedera Helix (or common English Ivy). The device monitors the plants environment and checks for a number of conditions such as soil moisture content, light intensity and temperature. A test is then carried out to ascertain whether or not the plant is happy (based on these three variables).
The device accesses a database of words which were used in Dutton & Swindells piece Free Association. These words have been categorised according to various perceived values of serenity. @calcutts_ivy picks a word which best reflects its mood and then tweets it.