added flexibility

src/motions/tetrahedral.h

@@ -0,0 +1,28 @@
+#ifndef RWSIM_MOTIONTETRAHEDRAL_H
+#define RWSIM_MOTIONTETRAHEDRAL_H
+
+#include "base.h"
+#include <random>
+#include <cmath>
+#include <array>
+
+class TetrahedralJump final : public Motion {
+public:
+    TetrahedralJump(double, double, std::mt19937_64&);
+    explicit TetrahedralJump(std::mt19937_64&);
+
+    void initialize() override;
+    double jump() override;
+
+private:
+    const double m_beta{std::acos(-1/3.)};
+
+    std::array<double, 4> m_corners{};
+    int m_corner_idx{0};
+
+    std::uniform_int_distribution<> m_chooser{1, 3};
+
+};
+
+
+#endif //RWSIM_MOTIONTETRAHEDRAL_H