"This is not a coincidence!"
Professor Liu's voice was like a crack of thunder.
He pushed through the crowd, completely ignoring Zhang Guilan, who was rolling on the ground.
His eyes were fixed only on the few glass marbles lying quietly on the ground.
"Old Liu, you..."
Professor Wang attempted to pull him back but was brusquely shoved aside.
Professor Liu rushed a few steps into the yard, crouched down directly, his expression fervent as if he were on a pilgrimage.
"Ah yo! You crazy old man, you stepped on me!"
He turned a deaf ear to Zhang Guilan's screaming.
From his pocket, he pulled out an object.
A small metal tape measure made in Germany.
With a "swish," the tape measure extended.
He began measuring.
From the release point under the porch to the landing point of the first marble.
From the marble's landing point to the patch of strawberry mud where Zhuangzhuang fell.
He muttered under his breath.
"The slope is 3.7 degrees..."
"Initial potential energy..."
