stairs=Graphics3D[{Yellow,Cuboid[{0.2,0,0},{0.4,0.2,0.38}],Yellow,Cuboid[{0.4,0,0},{0.6,0.2,0.4}],
Yellow,Cuboid[{0.6,0,0},{0.8,0.2,0.42}],Yellow,Cuboid[{0.8,0,0},{1.0,0.2,0.44}],
Yellow,Cuboid[{0.8,0.6,0},{1.0,0.78,0.5}],Yellow,Cuboid[{0.8,0.4,0},{1.0,0.6,0.48}],Yellow,Cuboid[{0.8,0.2,0},{1.0,0.4,0.46}],
Yellow,Cuboid[{0.2,0.2,0},{0.4,0.4,0.36}],Yellow,Cuboid[{0.2,0.4,0},{0.4,0.6,0.34}],Yellow,Cuboid[{0.2,0.6,0},{0.4,0.8,0.32}],Yellow,Cuboid[{0.2,0.8,0},{0.4,1.0,0.3}],Yellow,Cuboid[{0.4,0.8,0},{0.6,1.0,0.28}],Yellow,Cuboid[{0.6,0.8,0},{0.8,1.0,0.26}]},ViewPoint->{0.2,-2,2.8}];
Animate[
y1=0.7-0.195*t/2-Floor[t/6];
x1=1.45-0.188*t/2+3-3*Floor[t/6];
y2=0.183*(t/2-5.5)-1+Floor[t/12]+Floor[t/21];
x2=0.185*(t/2-8.9)+5-5*Floor[t/21]+5*Floor[t/26];
x3=0.85+5-5*Floor[t/26];
x=2;y=2;z=2;
z=(0.6-0.01*t);

tama1=Sphere[{0.9,y1,z},0.1];
tama2=Sphere[{x1,0.1,z},0.1];
tama3=Sphere[{0.3,y2,z},0.1];
tama4=Sphere[{x2,0.9,z},0.1];
tama5=Sphere[{x3,0.7,0.6},0.1];

Show[stairs,Graphics3D[{tama1}],Graphics3D[{tama2}],Graphics3D[{tama3}],Graphics3D[{tama4}],Graphics3D[{tama5}],PlotRange->{{0.2,1.0},{0,1.0},{0,1.0}}],{t,0,26,1/26}
]