Can someone suggest the best way to plot a directional 2D equilateral triangle?

I'm trying to write some simple code that will plot a 2D equilateral triangle, with the triangle center specified at a distance from an existing equilateral triangle, which is pointing at it? Any help offered would be greatly appreciated.

Answer 1

[DGM]

This is incomplete, but it should be a start.

r=10; % triangle radius

p0=[0 0]; % prior point [x,y]
p=[50 50]; % current point [x,y]

% offset angle based on distance vector
% this may already be known from prior triangle orientation
th=atan2d(p(2)-p0(2),p(1)-p0(1))+180; 

% calculate vertex locations
xv=r*cosd(th+[0 120 240 0]) + p(1);
yv=r*sind(th+[0 120 240 0]) + p(2);

% plot this triangle
plot(xv,yv)

xlim([0 100])
ylim([0 100])
axis equal

Answer 2

[Steve]

Thank you DGM. Can this code be modified to generate a connected series of equilateral triangles? I am ultimately looking to have many triangles (generated at specific centerpoint locations), where their vertices are all pointing at neighboring triangles' vertices (as depictred below). Thanks again for your help!

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[DGM]

I suppose it could. Mind you, it would be using plot tools to do so. If your goal is to generate a raster image directly, the drawing part might get a bit more complicated.

[Steve]

Raster images are definitely not needed; the triangle your code generates is actually perfect. I just provided the sketches to show sample triangle arrangements.

Also, ideally, if all the triangle center locations are given, I would like to be able to assign a single, initial triangle on one of the centers, with the orientation specified (always toward another triangle's center). Then, I would like to code to generate the rest of the oriented triangles from there on. Would this be possible with a modified version of your code? Attached is another sketch to show the idea. Thanks again!