**.subckt lots-of-inverters
V.100MHz in GND pulse(0 1.8 1ns 1ns 1ns 5ns 10ns)
V1.8 vcc GND pwl 0 1.8
**** begin user architecture code

.lib /usr/local/share/sky130_fd_pr/models/sky130.lib.spice tt
.tran 0.1n 1u
.save all

**** end user architecture code
**.ends
.GLOBAL GND
.end