**Application settings:**

Number of items:The number of stimuli in the task

Timer is enabledNo

Total task time (seconds):00:10:00

Enable backward - display the button for the previous item:Yes

Progress bar shows:ItemsTimeNothingIt will be displayed how many items are left to the end.

Demo mode:Off

Angle between two lines is given by formula:

tgα = tg(α2−α1) = (tgα2−tgα1) / (1+tgα1*tgα2) = |(k2−k1)/(1+k1*k2)|.

where k1 (α1) is the slope (angle) of the first line, k2 (α2) is the slope (angle) of the second line, and α (alpha) is the angle between them. The slope or gradient of a line is a number that describes both the direction and the steepness of the line [slope k=dy/dx=(y2-y1)/(x2-x1)]. Note: tg = tan = tangent.

The dependent variable in this task is the angle between the two lines. The maximum error (100%) is if the lines are perpendicular to each other (right angle, PI/2 or 90°). The error is shown as a deviation from the maximum error in percents.

Unit: percentages. The minimum possible error is 0% which is very difficult to achieve.

**Storage (useful for group research):**

Storage:NoYesThis web application will not store results within your web browser. Data is lost when the browser tab is closed

You have a total of 0 results stored in your web browser

dx = resolution in the x-axis direction (pixels). The width of each rectangle in the grid.

dy = resolution in the y-axis direction (pixels). The height of each rectangle in the grid.

Your browser probably doesn't have support for the Web Storage Object or access to the Storage Object is disabled. Check your browser settings. In some browsers (example: IE11) Storage Object is not enabled when accessed in a local file (offline).