They say that form follows function, and that's never more true than when it comes to chairs design. Over the year, the simple block on which to seat yourself has taken on design changes and elements to suit any specific chair for particular purposes. There are chairs for lounging, chairs for working, chairs for dining, chairs for feeding baby in and chairs for just about any purpose you can imagine. Take a look at the particular design specifics that go into suiting a chair for a particular task.

Kitchen and dining room chairs are the most common chairs made and most households have at least four of them. Generally, they have four legs, a seat and a back. The seat is most often 16 inches above the ground - the median height for comfort. The back is set at nearly right angles to the seat to encourage an upright posture - most comfortable for eating.

Easy chairs are designed for comfortable sitting for extended periods of time. Most often, the seat is designed to slant backward slightly and take some of the weight off the posterior, distributing it to the lower back. Easy chairs are often upholstered, but one common easy chair design, the Adirondack chair, is plain wood designed to encourage comfortable lounging without cushioning.

Task chairs are designed to encourage the worker to sit in a particular posture that is best for the task to be accomplished. Most modern task chairs are ergonomically designed to allow long periods of being seated without placing undue strain on the lower back, upper back or legs. Often, task chairs have a lumbar support to make sitting more comfortable.

Lounge chairs are designed for - what else? Lounging, of course. The backs may be designed to recline, and they often have an extended seat to allow the legs to be lifted and supported comfortably. The chaise lounge is a typical lounge chair.

Stacking and folding chairs were designed to make storage of extra seating easy. They are often designed to fit easily into each other when stacked to make it easy to store and stack a number of chairs one on top of the other. The most common of these are the ubiquitous plastic and metal bucket chairs with u-shaped legs that fit over each other to allow easy stacking.

Office chairs, particularly executive chairs, are a cross between easy chairs and task chairs. Most are ergonomically designed to make being seated for long periods of time comfortable. They are often padded, and covered with a material that reduces heat and friction. Body contour is taken into account, and the seat is often adjustable in both height and angle to allow the chair to be individually tailored for comfort by each user.

Every once in a while, a new wave of novelty chairs catches the public fancy. Many of these end up outliving their trendiness to become standards in the chairs industry. Among those that have been popular in the last 30 years are beanbag chairs, inflatable chairs, papasan chairs and directors chairs.