RandomVariate[NormalDistribution[],3]

YBK[n_]:=Module[{γ,p},
γ={{0,0,0},p=RandomVariate[NormalDistribution[],3]};
Do[AppendTo[γ,
p=p+RandomVariate[NormalDistribution[],3]-0.25p/Norm[p]+Sum[(p-q)(E^(-(p-q).(p-q))),{q,γ}]/Length[γ]
],
{n-1}
];
γ
];
γ=YBK[10000];
MinMax/@Transpose[γ]
Graphics3D[Line[γ]]

γ1=γ;

YBK[n_]:=Module[{γ,p},
γ={{0,0,0},p=RandomVariate[NormalDistribution[],3]};
Do[AppendTo[γ,
p=p+RandomVariate[NormalDistribution[],3]-0.25p/Norm[p]+2Sum[(p-q)(E^(-0.25(p-q).(p-q))),{q,γ}]/Length[γ]
],
{n-1}
];
γ
];
γ=YBK[10000];
MinMax/@Transpose[γ]
Graphics3D[Line[γ]]