Verse 20

इत्थं यथेह सामग्र्या स्वशक्तिस्थपदार्थया ।संपन्ना काकतालीया दृढा वरगृहाकृतिः

In plain words

"Just so, here, through materials each resting in its own power, a firm and excellent house-shape comes together by mere coincidence."