transformers face an array of issues that demand operating efficiency. some transformers have two or three modes of transformation for example: first mode / studying, reading, writing, second mode / comfortable sitting for relaxation and contemplation third mode / informal conferencing ... the main categories of these transformers are - transformers you can use in two (or more) different ways without changing mode; - transformers that change modes (the chair turns into...); - accessories are attached to the chair (linked); - accessories in use only for one mode, can be taken apart (not linked).