BlackHC

to determine the intersection point of 3 planes in R^3:

if the 3 planes are specified using 4-component vectors a,b,c (a * v = 0 if the homogeneous vector v is on plane a, etc)

build the 4x4 matrix

(
x y z w
a^T
b^T

BlackHC

bool hasCycle( Element *head ) {
	Element *guard = head;
	Element *current = head;
	bool updateGuard = false;
	while( current ) {
		current = current->next;
		if( current == guard ) {
			return true;
		}
		if( updateGuard ) {

BlackHC

  void drawEighthOfCircle( int radius ) {
	int y = radius;
	int x = 0;

	// invariant: radius^2 <= x^2 + y^2 < (radius+1)^2
	int maxLength = (radius+1)*(radius+1);
	while( x <= y ) {
		setPixel( x, y );

		x++;

BlackHC

to determine the intersection line of two planes

planes A, B given by R^4 vectors, so that A*x = 0 if x on A, x homogeneous in R^4.

det( A, B, *, * ) is the solution space of all intersection vectors in R^4.

det( A, B, (0 0 0 1), * ) is the solution space of the direction vector d. extract it by pulling it into a R^4 vector d = (* 0).

det( A, B, *, d ) is the solution space of a point on the line. extract it by pulling it into a R^4 vector s.

BlackHC

// ----
// Sass (v3.4.4)
// Compass (v1.0.1)
// ----

feature-info {
  shadowing: feature-exists(global-variable-shadowing);
}
$var: red;

BlackHC

// ----
// Sass (v3.4.4)
// Compass (v1.0.1)
// ----

feature-info {
  shadowing: feature-exists(global-variable-shadowing);
}
$var: red;

BlackHC

/**
 * The first commented line is your dabblet’s title
 */

background: #f06;
background: linear-gradient(45deg, #f06, yellow);
min-height: 100%;

BlackHC

<table class="mytable">
  <tfoot>
    <tr>
      <td class="mytd">
        Hello
      </td>
    </tr>
  </tfoot>
</table>

BlackHC

<table class="mytable">
  <tfoot>
    <tr>
      <td class="mytd">
        Hello
      </td>
    </tr>
  </tfoot>
</table>

BlackHC

<table class="mytable">
  <tfoot>
    <tr>
      <td class="mytd">
        Hello
      </td>
    </tr>
  </tfoot>
</table>