Using OneStone® Pebbles
The User Interface (UI) of the Curve Families Pebble is pictured at right; as described
on the Pebbles Home page, all Pebbles
UIs are similar, so the following procedure applies equally to them all. The
procedure is also summarized in an animated .gif which can be seen
here.
 Start the Pebble by clicking the 'Launch...' link on that Pebble's web page.
Pebbles are designed to download themselves on each use, as described
here. This ensures you always run the latest version available.
The size of each is around 200 KB so it should download in just a few seconds.
 Enter an expression in the text box at upper left. There are individual
restrictions on the expression a Pebble operates on; for instance, the Surfaces
of Revolution Pebble only accepts the variables 'X' or 'Y', while the Curve Families
Pebbles accepts 'Theta' and 'R', as well. These differences are noted on a particular
Pebble's web page and in it's Help file. The list of operators recognized by all
Pebbles appears below.
 Select a constant from the dropdown list. The dropdown list below
the expression is automatically loaded with any numeric constants present in the
expression. The first constant in the list is automatically selected, appropriate
minimum and maximum values are calculated, and the slider is set to the original
value of the constant. These minimum, maximum and current values can all be edited
directly, as well.
 Drag the slider to vary the selected constant. The curves/surfaces
will smoothly animate in response to the sliders motion. At the same time, the current
value display will change to reflect the new value, and the full modified expression
is shown below the slider with the selected constant highlighted.
 Click and drag the 2D display window to shift the graphed region.
Both displays update in real time as the 2D surface is dragged. Zoom controls below
the modified expression display can also be used.
 Click and drag the 3D display to change the viewing angle. The
colors of visual elements can be changed, as well, to improve contrast/visibility.
Expression Syntax
The expressions accepted by Pebbles are caseinsensitive ('SIN' works as well as
'sin'), but, as indicated below, both upper and lower case E's are valid operators
('E' is the exponential operator, shorthand for 'times ten to the power of', and
'e' is the natural log constant 2.71828...) so care must be taken. Blank spaces
are accepted. Implied multiplication is recognized, but unequivocal use of parentheses
is strongly encouraged.
The tables below list the operators accepted by all OneStone Pebbles.
Basic Math Operators
+ 
 
* 
/ 
( 
) 
ln 
log 
E 
^ 
abs 
sqrt 

Constants

Trig Operators
sin 
arcsin 
cos 
arccos 
tan 
arctan 

Hyperbolic Trig Operators
sinh 
arcsinh 
cosh 
arccosh 
tanh 
arctanh 

