A nice little figure illustrating an infinitesimal neighbourhood around a given point.  This was used as a figure in the somewhat tedious verification of a Green’s function, done in one of the appendixes.

<<peeters`

(*relative to ~/physicsplay*)
peeters`setGitDir[ "../project/figures/GAelectrodynamics" ]

ClearAll[e1,e2,e3,x, xp, xpp, o, r, ncap]

o = {0,0,0};
{e1,e2,e3} = IdentityMatrix[3];
x = {1,2,3}/2;
r = 0.5;
ncap = {1,1,0.3}// Normalize;
xpp= r ncap;
xp = x + xpp;

tArrow := Arrow[Tube[#]]&;
bold = Style[#,Bold] &;
fs = Style[#, FontSize->14]&;
esub = fs[Subscript[ "e" // bold , #]] &;

Graphics3D[ {
Black,
tArrow[{o,e1}],
tArrow[{o,e2}],
tArrow[{o,e3}],
Blue,
tArrow[{o,x}],
Text["x" //bold//fs,x/2+ e3/3],
Green// Darker,
tArrow[{o,xp}],
Text["x'" //bold//fs,0.6xp - e3/5],
Red // Darker,
tArrow[{x,xp}],
Text["x''" //bold//fs,x + xpp/2 + e3/5],
Black,
Text["(OverHat[n])" //bold//fs,xp + 1.1 ncap],
tArrow[{xp, xp +ncap}],
Text[esub[1],1.1 e1],
Text[esub[2],1.1 e2],
Text[esub[3],1.1 e3],
Opacity[0.5],
Orange,
Sphere[x,r]
}]

p = ;

peeters`exportForLatex["neighbourhoodFig1", p]