This photo is adorable. It’s also a perfect explanation of Oklahoma’s school funding crisis.

Nothing has symbolized the school funding crisis in Oklahoma quite like images of old, tattered textbooks that students still use.

Photos of textbooks with missing pages and duct-taped spines have gone viral on social media. Not to mention the geography books published when the Soviet Union still existed, or social studies books that were new three presidencies ago.

Of all the photos, this one posted below by a mom and former school teacher from Ada, Oklahoma, might be the most disheartening.

In a Facebook post, Shelly Bryan Parker describes how excited her daughter was to find out that country music star Blake Shelton used her first-grade reading textbook. Then she describes how ashamed she was when she realized that Shelton is 41 and used that same book 36 years ago — back when it was new.

The photo explains why Oklahoma teachers are so angry with lawmakers, and why they’ve been on strike for seven days. They are pushing back against a decade of state tax cuts that triggered deep cuts in education spending, forcing about 20 percent of public schools to switch to a four-day-week schedule and pushing average teacher salaries to rank 49th in the country. Teachers haven’t gotten a raise in 10 years.

Even though lawmakers agreed to boost their pay, teachers say it’s not enough. They want the state to restore more than $200 million in funding for public schools cut from the budget since 2008.

And they want their kids to have textbooks that aren’t as old as Blake Shelton.