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  "body": "\n## Summary\n\nA function on the unit ball has a nontangential limit at a boundary point if it converges along every approach inside a cone.\nThe cones have their vertex at the boundary point.\nSuch cones, called Stolz angles in the plane, keep the approach away from tangential directions.\nNontangential limits are the right notion of boundary value for harmonic and holomorphic functions.\n[[Fatou's theorem|Q2N917JQ6A]] says that Poisson integrals and bounded holomorphic functions have them almost everywhere.\n\n## Explanations\n\n### L1 human\n\nWalk towards a point on the boundary circle of the unit disc.\nIf you come in at an angle, staying inside a fixed wedge with tip at the point, you approach nontangentially.\nA function has a nontangential limit if it tends to one value along all such walks.\nWalks that hug the circle, tangential walks, are allowed to give other values.\nFor example, $\\exp\\left(-\\frac{1 + z}{1 - z}\\right)$ tends to $0$ at $1$ nontangentially, but has modulus $1/e$ on a circle through $1$ tangent to the unit circle.\n",
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