He was one of the first British artists to experiment with machine-generated visual effects at the time of the emerging global computer art movement of the 1960s (The Cambridge Encyclopaedia 1990 p. 289; Levy 2006 pp. 178–180).

During this period, Henry constructed a succession of three electro-mechanical drawing machines from modified bombsight analogue computers which were employed in World War II bombers to calculate the accurate release of bombs onto their targets (O'Hanrahan 2005).

Henry's machine-generated effects resemble complex versions of the abstract, curvilinear graphics which accompany Microsoft's Windows Media Player.

Lowry insisted Henry also include some machine drawings alongside his photo-chemical ones, in the London exhibition of August 1962 called "Ideographs" (O'Hanrahan 2005).

"Cybernetic Serendipity" then went on to tour the United States, where exhibition venues included the Corcoran Gallery in Washington and San Francisco's Palace of Fine Arts (O'Hanrahan 2005).

More recently, frequent mechanical and/or electronic computer breakdowns contributed to the decision to close Artworks, (The Lowry, Salford Quays, Manchester) in March 2003 after only three years in operation as a permanent, technology-based, interactive exhibition (O'Hanrahan 2005).

The mechanical analogue bombsight computer was employed in World War II bomber aircraft to determine the exact moment bombs were to be released to hit their target.

It was in 1952 that Henry purchased his very first Sperry bombsight computer, in mint condition, from an army surplus warehouse in Shude Hill, Manchester.

These machines created complex, abstract, asymmetrical, curvilinear images, which were either left untouched as completed drawings or embellished by the artist's hand in response to the suggestive machine-generated effects.

That is to say, they relied upon the chance relationship in the arrangement of each machine's mechanical components, the slightest alteration to which, (for example, a loosened screw), could dramatically impinge on the final result.

In 2001 Henry's machine-generated work was discussed in terms of the use made, since earliest times, of a range of tools for producing similar abstract, visual effects (O'Hanrahan 2001).

However Henry's drawing machines, in contrast to other precision mark-making instruments like the lathe and mechanical plotter, relied heavily upon the element of chance both in their construction and function (O'Hanrahan 2005).

Each Henry machine-produced drawing bears all the hallmarks of a fractal image since they embody regularity and repetition coupled with abrupt changes and discontinuities (Briggs 1994[1992]).

These images also resemble fractal "strange attractors", since groups of curves present in the machine-generated effects tend to form clusters creating suggestive patterns (Briggs 1994[1992]).

Fractal patterns, similar to Henry's machine-generated effects, have been found to exist when plotting volcanic tremors, weather systems, the ECG of heart beats and the electroencephalographic data of brain activity (Briggs 1994[1992]).

Among the many artists who have previously employed what are now recognised as fractal images, are: "Vincent van Gogh's dense swirls of energy around objects; the recursive geometries of Maritus Escher; the drip-paint, tangled abstractions of Jackson Pollock" (Briggs 1994[1992] p. 166).

This is in contrast to Henry who had to acquire the necessary knowledge and skills to manipulate and modify the components of the bombsight computers in order to construct and operate the drawing machines (O'Hanrahan 2005).

Firstly, the bombsight analogue computer provided not only the inspiration but also the main tool for producing highly original visual effects (O'Hanrahan 2005).

Thirdly, the spontaneous, interactive potential of his drawing machines' modus operandi pre-empted by some twenty years this particular aspect of later computer graphic manipulation software (O'Hanrahan 2005).

As a result, The drawing machines and their visual effects represent pioneering precursors to the Digital Art produced by today's computer software.

He much preferred the direct interaction afforded by the clearly visible interconnecting mechanical components of the earlier analogue computer and as a consequence of his drawing machines also.