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The special aniline dyes for making the master image came in the form of ink or in pens, pencils, carbon paper and even typewriter ribbon. Hectograph pencils and pens are sometimes still available. Various other inks have been found usable to varying degrees in the process; master sheets for spirit duplicators have also been pressed into ...
Four planes from the axial pencil on P1 P2. A pencil of planes, is the set of planes through a given straight line in three-space, called the axis of the pencil. The pencil is sometimes referred to as a axial-pencil [7] or fan of planes or a sheaf of planes. [8]
In addition to the mastery of the mechanics of drawing lines, arcs and circles (and text) onto a piece of paper—with respect to the detailing of physical objects—the drafting effort requires a thorough understanding of geometry, trigonometry and spatial comprehension, and in all cases demands precision and accuracy, and attention to detail ...
The pens are offset from their pivots by a short stem that projects at right angles from below the midpoint of the pen, allowing the pen to be grasped in whatever way is usual to the user. ("a" on diagram) Pen tilt (fore and aft): A torsion beam joins the pen mounts to maintain correspondence of tilt with respect to the direction away from the ...
Once either of these rings were held in place (either by pins, with an adhesive, or by hand) any of several provided gearwheels (or rotors)—each having holes for a ballpoint pen—could be spun around the ring to draw geometric shapes. Later, the Super-Spirograph introduced additional shapes such as rings, triangles, and straight bars.
In most cases, the final drawings are drawn with ink, on either plastic or tracing paper. The pen is generally a Rapidograph-type technical pen, a marker pen that draws lines of consistent width (so-called steel marker pen). The pen has an ink container which contains a metal tube, inside which is a thin metal needle or wire, the soul.
The "nine dots" puzzle. The puzzle asks to link all nine dots using four straight lines or fewer, without lifting the pen. The nine dots puzzle is a mathematical puzzle whose task is to connect nine squarely arranged points with a pen by four (or fewer) straight lines without lifting the pen or retracing any lines.
Leonardo da Vinci's Vitruvian Man (c. 1485) Accademia, Venice. Drawing is a visual art that uses an instrument to mark paper or another two-dimensional surface. The instruments used to make a drawing are pencils, crayons, pens with inks, brushes with paints, or combinations of these, and in more modern times, computer styluses with graphics tablets or gamepads in VR drawing software.