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The Mechanical Universe

Draw with your finger


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Regular Expression Basics : How many Matches?
A Regular Expression (regex) is a sequence of characters that define a pattern that allows you to search, match, locate, replace, manipulate, and manage text. In this article you'll learn how to use regular expressions to count the number of matches. More ...

Processor Interrupts
An interrupt is a signal to the processor indicating an event has occurred that needs immediate attention. When an interrupt occurs, the processors normal path of execution is interrupted in order to run a routine to service the interrupt requester. More ...

Introduction to Draw SVG Free Online SVG Drawing Application
A drawing created on a computer can be posted directly on the Web. Drawing on a computer with a vector drawing program is the best way to go. Draw SVG seems to meet the need. In this article I touched on only a tiny part of what Draw SVG can do. More ...

Regular Expression Position Matching
In this article you how to use regular expressions to match characters at the beginning, end, both beginning and end, or at any specified location in a string. More ...

Capacitors
A capacitor is an electronic component that can store electric charge. A capacitor is constructed with two conductive plates separated by an insulator called a dielectric. More ...

Inkscape Preferences
Inkscape is a highly configurable application. Many of these configuration options can be set through the Preferences dialog box. There is probably a hundred things you can configure through the Preferences dialog box. Here I'll describe a couple of the most important ones. More ...

The Power of a Positive Attitude
One of the most important personality traits required for the achievement of a successful life is a positive attitude. What I mean when I say positive attitude might be more accurately described as a realistic attitude. More ...

JavaScript to Copy and Paste Text to the Clipboard
In some applications, rather than the user's selection, you may want to copy the contents of a specific html element to the clip board. Or when the user initiates a Paste, you may want to direct the contents of the user's clipboard to a specific html element on the webpage. Here is the code for this. More ...

Learn Assembly Language Programming on Raspberry Pi 400
One of the easiest ways to learn assembly language programming is on the Raspberry Pi 400. The Raspberry Pi 400 is a complete personal computer built into a compact keyboard. More ...

What is an Ethernet Crossover Cable?
When connecting two computers together without a switch or router in between you need a special cable, called a crossover cable, that has the transmit wire pair swapped with the receive wire pair. More ...

Minispreadsheet
Minispreadsheet is a tiny extremely easy to use spreadsheet, You can type text into a cell, you type a number into a cell. A formula is a simple list of cells with basic mathematical operators between them. If you change the number in a cell used in a formula in a different cell, the value in the cell with the formula will be updated. More ...

Regular Expressions Lookarounds
In this article you learn how to match a pattern only when it comes after another pattern (or after not that pattern) or only when it comes before another pattern (or before not that pattern). More ...

Regular Expressions Subexpressions
In this article you learned how to use subexpressions to rearrange matches in a regular expression and how to replace the value of a subexpression match in the results. More ...

Regular Expression Basics : Match a Set of Characters
A Regular Expression (regex) is a sequence of characters that define a pattern that allows you to search, match, locate, replace, manipulate, and manage text. In this article you'll learn how to use regular expressions to match a set of of characters. More ...

Area of a Quadrilateral Calculator
If you have a regular quadrilateral there are simple formulas to calculate the area. But if you have an irregular quadrilateral you can calculate its area by viewing it as two triangles bucked up against one another. Find the area of each triangle, and then add them together. More ...

Inkscape Layers and Z-Order
Inkscape's use of the Z axis is represented by layers and is called z-order. When you first draw an object on an empty canvas, it has a z-order of 1. If you draw a second object, it has a z-order of 2. If you draw a third object, it has a z-order of 3 and so on. More ...


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